《參同契闡幽》Vol. 2

The Cantongqi (Kinship of the Three) is an essential Daoist scripture composed by the Perfected Lord Wei Boyang during the Eastern Han dynasty, later profoundly elucidated by Master Zhu Yuanyu of the Cloud Yang lineage. This classic's core philosophy employs the principles of the Yijing (Book of Changes) to illuminate the theory of alchemical cultivation. The essence of the Yijing lies in the transformations of Yin-Yang, and the practice of alchemical cultivation similarly depends on their dynamic interplay. The union of Yin-Yang forms the foundation of the Yi, within which the principles of the Great Dao are also contained.

"Can" (參) signifies cross-referencing, "tong" (同) denotes synthesis and integration, while "qi" (契) implies seamless harmony. The text is divided into three sections—upper, middle, and lower—each encompassing three aspects: "governing affairs" (御政, metaphorical statecraft), "nourishing nature" (養性, self-cultivation), and "ingesting the elixir" (伏食, alchemical refinement). Only by interrelating these three—the philosophy of the Yijing, the life-nourishing teachings of the Yellow Emperor and Laozi, and the methods of alchemy—can one truly comprehend the Great Dao of the dual cultivation of nature and life (性命雙修). Understanding any one aspect inherently encompasses the others.

The upper section (上卷) primarily discusses "governing affairs" across five chapters. Though this portion emphasizes metaphorical statecraft, it already contains the principles of nourishing nature and alchemy. The so-called "governing affairs" employs the hexagrams of Qian (Heaven), Kun (Earth), Kan (Water), and Li (Fire) to symbolize the relationship between ruler and minister: the ruler governs through non-action (Wuwei), while the ministers act with purposeful engagement—precisely the foundational principles of both self-cultivation and alchemy. Hence, it concludes by referencing the Yijing's teachings on innate nature and emotions.

The first chapter, "Qian and Kun as the Gateway," states: The Qian (Heaven) and Kun (Earth) hexagrams are the gateway to the Yijing, the root of all other hexagrams. Kan and Li function like the frame of a wheel, while the remaining four hexagrams operate like bellows, governing the patterns of Yin-Yang transformation. Just as a charioteer must grasp the reins and follow the rules, so too must the Daoist practitioner master the rhythm of Yin-Yang changes. The year's twelve months divide into six Yin and six Yang; the day's twelve two-hour periods (時辰) also alternate between Yin and Yang. The sixty-year Jiazi cycle balances firmness and yielding. Beginning with the Zhun hexagram at the new moon (朔日) and concluding with the Weiji hexagram at the month's end (晦日), each day and night corresponds to a hexagram in continuous cyclical motion. The sun and moon follow their own laws, their movement and stillness alternating between early and late phases. In spring and summer, Yang Qi resides within, from the Zi hour (子時) to the Si hour (巳時); in autumn and winter, Yang Qi moves outward, from the Wu hour (午時) to the Hai hour (亥時). Reward and punishment must align with the seasons, while activity and rest must follow the shifts of cold and heat. The hexagram line statements contain the principles of benevolence and righteousness, requiring the practitioner to adjust cultivation rhythms according to the seasonal cycles. Only then can one harmonize with the patterns of the four seasons and Five Phases (五行), attaining unity with the Great Dao of Heaven and Earth.

This chapter begins by elucidating how "Qian and Kun" (symbolizing heaven and earth's fundamental principles) encompass all phenomena like a gateway, serving as the overarching framework of the entire scripture. In the Book of Changes (Yijing), Qian and Kun act as parents to all hexagrams, while Kan and Li (symbolizing water and fire) function like the wheel's rim, driving the cosmic axis of rotation.

Here we encounter the fundamental laws of Yin-Yang transformation contained within Qian and Kun. The most essential elements between heaven and earth are this pair of Yin and Yang: their unchanging essence is called "Dao," their transformative mechanism is called "Change" (Yi), and their miraculous function is called "Elixir" (Neidan practice). While the Book of Changes discusses Yin-Yang through Qian-Kun, the alchemical path manifests Yin-Yang through the dual cultivation of nature and life (xingming) - indeed, Qian and Kun represent the very essence of xingming. But to truly comprehend this, one must trace the mystery preceding life's formation.

During the primordial chaos before creation, when even the most fundamental "Qi" (primordial energy) hadn't manifested, this state was beyond description or naming - only boundless emptiness without form or substance, the true "void." Yet this emptiness contained infinite potential, termed "marvelous existence." This "apparent existence that is actually void" state may provisionally be called "the beginning of heaven and earth," while the "apparently void yet containing existence" state may provisionally be termed "the mother of all things."

This "existence as void" state reveals how Taiji (cosmic origin) emerges from Wuji (infinite void), while "void as existence" shows how Wuji gives birth to Taiji. The Taiji essence originally transcends movement and stillness: appearing dynamic yet maintaining unchanging nature, this is Qian's (heaven's) characteristic from which the light, pure Qi arises; appearing still yet containing vitality, this is Kun's (earth) characteristic establishing substantial heaviness. Between these transformations emerges humanity as "the heart of heaven and earth," containing within it the Book of Changes' principle of perpetual regeneration.

Though the embryonic form of life exists, it remains in undifferentiated chaos, hence called "Taiji containing three." When stillness reaches its peak and moves, Qian's Yang energy penetrates earth's depths, which Kun receives to form Kan (water) - Yang within Yin. This is "heaven's one generating water" - manifesting as water on earth and the moon in heaven. When movement peaks and returns to stillness, Kun's Yin energy ascends to heaven's heights, which Qian governs to form Li (fire) - Yin within Yang. This is "earth's two generating fire" - manifesting as fire among humans and the sun in heaven. Thus Taiji generates the two polarities (Yin-Yang), which in turn generate the four phenomena (greater/smaller Yin and Yang). Without sun and moon, heaven-earth cannot manifest their wonders; without Kan-Li, Qian-Kun cannot operate creation. Therefore the Dao of Changes must take Qian-Kun as its foundation.

This passage explains the pivotal role of the four hexagrams Qian (Heaven), Kun (Earth), Kan (Water), and Li (Fire) from the Book of Changes (Zhouyi) in Neidan (internal alchemy) practice. Qian and Kun represent Heaven and Earth, the foundation of Yin-Yang, akin to parents giving birth to six children (the hexagrams Zhen, Xun, Kan, Li, Gen, and Dui). Among these, Kan and Li hold special significance because they inherit the purest qualities of Qian and Kun—Kan (Water) receives the central line of Qian, while Li (Fire) receives the central line of Kun.

In the Prenatal (Xiantian) Bagua arrangement, Qian resides in the south and Kun in the north, with their central lines exchanging to form Kan and Li. In the Postnatal (Houtian) arrangement, Li moves to the south and Kan to the north. Though their positions shift, the framework of Heaven and Earth (Qian and Kun) remains constant, while Kan and Li function like the sun and moon circulating within it, governing the alternation of day and night, the cycle of seasons, and even greater temporal rhythms. This resembles the turning of a wheel: the axle (Kan and Li) relies on the hub (Qian and Kun) to rotate, yet the entire cart's movement depends on the axle.

In Neidan practice, Qian and Kun symbolize the furnace and cauldron for refining the elixir, while Kan and Li represent the crucial elements of the medicinal ingredients and the firing process. Just as the hub and axle work in harmony, alchemical cultivation requires mastering the principles of Yin-Yang circulation. This echoes Laozi’s teaching: "Thirty spokes share one hub; it is precisely because of its emptiness that the cart is useful."

The passage concludes by referencing the four hexagrams of Yin and Yang (symbolized as female and male) as bellows (metaphor for breath regulation), encompassing the patterns of Yin-Yang transformation. Like a skilled charioteer steering with reins, the practitioner must follow cosmic laws, attuning to the rhythms of Yin-Yang waxing and waning (lüli, or calendrical cycles), maintaining inner equilibrium while harmonizing with external changes. Ultimately, this reveals the core principle of Neidan: using Qian and Kun as the foundation (ti) and Kan and Li as the function (yong).

This passage explains the relationship between Yin-Yang transformations and the regulation of fire times (huohou) in cultivation. The Qian (Heaven) and Kun (Earth) trigrams—the two fundamental symbols representing cosmic forces—transform into Kan (Water) and Li (Fire), driving the movement of Yin and Yang like the bellows of a forge.

Originally, the pure Yang Qian trigram symbolizes masculinity, but when its central line transforms to form the Li trigram (containing a Yin line), masculinity shifts to femininity. Conversely, the pure Yin Kun trigram symbolizes femininity, yet when its central line changes to form the Kan trigram (containing a Yang line), femininity reverts to masculinity. This metamorphosis resembles the unfathomable depths of an abyss (Kun transforming into Kan) and the ceaseless flow of celestial breath (Qian becoming Li), echoing Laozi’s words: "Is not the space between Heaven and Earth like a bellows (tuoyue)?"

Though four trigrams (Qian, Kun, Kan, Li) are mentioned, the essence lies in the dynamic interplay of Kan and Li energies. Their movement follows the precision of day and night or the cycle of seasons, forming the foundation for the transformations of the sixty hexagrams and their 360 lines. Like driving a chariot—horses have reins, and the cart follows tracks—the true mastery lies in the driver’s rhythmic control. This is the crux of regulating fire times in cultivation.

The text further describes using the twelve pitch pipes (lülü) and twelve earthly branches (shichen) to standardize fire times, emphasizing that Yin-Yang cycles must align with the exactitude of musical harmonics. Each lunar month’s thirty days divide into six phases (five days per phase), harmonizing with the sixty hexagrams to balance hardness and softness. Beginning with the Zhun hexagram on the new moon (shuo) and concluding with the Meng hexagram at the month’s end (hui), each day and night corresponds to a hexagram, cycling endlessly. This section details how to align the minor celestial orbit (xiaozhoutian) with lunar phases to refine fire times.

(Note: "Tuoyue" refers to an ancient bellows; "fire times" denote breath regulation in Neidan (internal alchemy); "celestial orbit" describes the cyclical circulation of Qi within the body.)

This passage explains how the Zhouyi Cantongqi (The Seal of the Unity of the Three) employs the sixty-four hexagrams to model the "fire times" (huohou)—the methods of regulating breath during cultivation. Excluding the four hexagrams of Qian (Heaven), Kun (Earth), Kan (Water), and Li (Fire), which represent the furnace, cauldron, and medicinal substances in alchemical practice, the remaining sixty hexagrams with their 360 lines correspond precisely to the 360 degrees of the celestial circle. The central lines of the Kan and Li hexagrams symbolize the sun and moon respectively, while the Qian and Kun hexagrams govern the overarching laws of celestial movement.

In the numerical symbolism of Yin-Yang, five represents the central Yang number, and six represents the central Yin number. Their product, thirty, signifies the days of a lunar month. The interplay of the sun and moon's movements creates the phases of the crescent, full moon, and the dark moon (new moon). The moon's waxing and waning always follows the sun's path, much like a minister obeying a ruler—hence the phrase, "The lunar phases have five and six, weaving their course in service to the sun." Over thirty days, the sixty hexagrams unfold completely, starting with Zhun (Difficulty) and Meng (Youthful Ignorance) and concluding with Jiji (After Completion) and Weiji (Before Completion), completing a full monthly cycle.

The hexagrams are divided into inner and outer forms, featuring "inverted pairs" (such as Zhun-Meng or Xu-Song, where one transforms into the other) and "mirrored pairs" (such as Zhongfu and Xiaoguo, which correspond to each other). For example, Zhun, with Yang energy below, symbolizes dawn, while Meng, with Yang energy above, symbolizes dusk—two sides of the same phenomenon. Beginning with Zhun-Meng on the new moon (the first day of the month) and ending with Jiji-Weiji on the last day, the sixty hexagrams complete a lunar cycle before restarting anew.

The latter section discusses adjusting cultivation practices according to the seasons: in spring and summer, when Yang energy ascends, the focus is from midnight to mid-morning (the Zi to Si hours); in autumn and winter, as Yin energy grows, the emphasis shifts from noon to late night (the Wu to Hai hours). Just as a ruler dispenses rewards and punishments in harmony with the seasons, cultivation must align with the rhythms of the Five Phases. The solstices (winter and summer) and equinoxes (spring and autumn) are critical junctures for regulating the "fire times" throughout the year. The sun governs daylight, peaking at noon (Wu hour) when Yang is strongest, while the moon governs nighttime, peaking at midnight (Zi hour) when Yin is most potent. Practitioners must seize these moments of Yin-Yang transition.

(Note: "Fire times" refers to the modulation of breath and intention in Neidan (internal alchemy) practice; "Zi hour, Wu hour," etc., follow the traditional twelve two-hour periods of the day; the "solstices and equinoxes" are the four pivotal nodes among the twenty-four solar terms.)

This passage explains the principles of regulating the "firing times" (huohou) during Neidan (internal alchemy) practice, where the cyclical changes of Heaven and Earth's Yin-Yang correspond to human cultivation. The daily, monthly, and yearly cycles all have their counterparts in practice. Just as the Zhun hexagram (symbolizing nascent Yang energy) initiates the "firing" process at the Zi hour (11 PM - 1 AM), with each ascending line representing increasing Yang until reaching pure Yang at the top line—mirroring the growth process of spring and summer—so too does the Meng hexagram (symbolizing nascent Yin energy) begin "cooling" at the Wu hour (11 AM - 1 PM), descending to pure Yin at the bottom line, corresponding to autumn and winter's harvesting phase. This illustrates the critical Yin-Yang interchange points of winter and summer solstices.

During the spring equinox when the sun resides in the Mao position (east), Yang contains traces of Yin, akin to benevolence (De) concealing discipline. At the autumn equinox when the moon dominates the You position (west), Yin harbors sparks of Yang, like justice containing rewards. The sun rising in the Yin position (northeast) and setting in the Shen position (southwest) symbolizes fire Qi generating summer heat, while the moon emerging from Shen and descending into Yin represents water Qi bringing winter cold. This embodies the principle of "harmonizing brightness with seasonal changes"—where humaneness governs growth and righteousness oversees restraint, with each hexagram line reflecting these thermal fluctuations. Joy aligns with rewards and anger with punishments, yet both must follow seasonal rhythms without excess—this constitutes the "bathing" (regulatory intervals) principle of the equinoxes.

By thus mastering the Four Seasons and Five Phases, ensuring Water, Fire, Wood, and Metal each occupy their proper positions, the central "true Earth" Qi mediates their interactions, allowing the harmonious fusion of Yin and Yang to crystallize the Golden Elixir. While earlier passages described lesser celestial cycles (xiaozhoutian) corresponding to monthly rhythms, this section addresses greater celestial cycles (dazhoutian) mirroring annual patterns. The essence of cultivation lies in the "compression" method—condensing a year's cycle into a month, a month's cycle into a day, and a day's cycle into an hour, ultimately encapsulating all movement and stillness within a single ke (15-minute period). Herein, the waxing and waning of Yin-Yang relies entirely on the bellows-like interplay of Kan (Water) and Li (Fire)—the fundamental mechanism encompassing the great Dao of Yin and Yang.

This scripture employs cosmological imagery to illustrate the operational principles of the human body as a microcosm. The human form resembles a miniature universe, with each bodily component corresponding to the symbolic representations of the eight trigrams (Bagua: Qian, Kun, Zhen, Xun, Gen, Dui, Kan, Li).

The head corresponds to the Qian trigram, symbolizing the Heavenly Father, while the abdomen aligns with the Kun trigram, representing the Earthly Mother. The feet correspond to Zhen (eldest son) and the legs to Xun (eldest daughter), both belonging to the earthly realm. The hands relate to Gen (youngest son) and the mouth to Dui (youngest daughter), associated with the celestial sphere. The ears correspond to Kan (middle son) and eyes to Li (middle daughter), positioned between heaven and earth as embodiments of the human dimension. All limbs, joints, and pores distribute throughout the body like the myriad lines of the hexagrams.

Yet these are merely the visible, tangible manifestations. More essential is the formless, primordial state before physical conception. Prior to parental conception, human nature exists in perfect wholeness - luminous and untainted, requiring no cultivation. This is the original state of "the Supreme Ultimate (Taiji) encompassing all existence." When a spark of spiritual light descends from the Great Void (cosmic origin) to take residence in the central palace (Dantian region), becoming the sovereign of life, this manifests as "each entity containing its own Taiji."

As primordial Qi begins to stir, the Great Void's energy enters through the nostrils, ascending to the Celestial Valley (crown of the head) and descending to the Sea of Qi (lower Dantian). The Qian (heaven) trigram descends to interact with Kun (earth): when the middle line of Kun becomes solid, it transforms into Kan (water), forming the root of life. Conversely, Kun ascends to interact with Qian: when the middle line of Qian breaks, it becomes Li (fire), establishing the foundation of spiritual nature. At this moment, with the severing of the umbilical cord, nature and life separate like the moon dividing into its waxing and waning phases.

In postnatal existence, the crucial dynamic lies in the interaction of Kan and Li: Kan's energy sinks deep into the Sea of Qi like an unfathomable abyss, while Li's light rises to the Celestial Valley, penetrating the highest heavens. Breathing mirrors the celestial dance of sun and moon, opening and closing between heaven and earth. The entire life process operates like a bellows (tuoyue), with the ascending and descending movements of Kan and Li energies driving its rhythm.

The movements of heaven and earth manifest in the alternation of day and night and the cycle of seasons, just as the human body contains these same patterns of waxing and waning Yin and Yang. If a Daoist practitioner can open the body's "gates" (referring to key acupoints in cultivation), they may perceive the mystery of the inner cosmos (Yin-Yang) operating like a furnace and cauldron. By activating the body's central pivot (regulating Qi), they can gather the two essential "medicinal substances" of Kan (Water) and Li (Fire) needed for practice. Through rhythmic stimulation of Qi (breathing like a bellows), they can apply the methods of Yang Fire and Yin Talisman (refining techniques corresponding to the sixty hexagrams). This embodies the principle: "Following the natural order makes an ordinary person; reversing it makes an immortal"—ordinary growth follows nature's course, while alchemical refinement reverses it to forge the Golden Elixir (Jindan).

Chen Xiyi (a renowned Song Dynasty Daoist) explained: The sun represents heaven's Jing-Qi (essential energy), descending westward to interact with earth's Qi; the moon represents earth's Jing-Qi, ascending eastward to commune with heaven's Qi—much like the union of man and woman creates life. Heaven and earth themselves don't produce seasonal changes; temperature variations arise from the sun and moon's relative distances. The cycle of seasons isn't actively caused by heaven and earth but results from the sun and moon's north-south movement. Even the moon's phases (new and full) derive from their celestial dance. Though Yin-Yang seems mysterious, its essence lies in solar-lunar motion; though creation appears vast, its foundation rests on the interplay of Kan and Li (Water-Fire). Just as all hexagram transformations ultimately depend on Kan and Li's core lines—like thirty spokes converging on a wheel's hub.

This chapter emphasizes the wondrous function of Kan and Li (Water-Fire), focusing on grasping the "central unity" (Yin-Yang equilibrium). The opening wheel metaphor highlights cultivation's need to seize this pivotal axis. Though Kan and Li have no fixed positions (circulating dynamically through the body), they permeate the six voids (bodily spaces), moving unpredictably yet invisibly driving all transformation—the very framework of the Dao's operation. They govern tangible reality through formless power, like empty vessels holding substance. Observing solar-lunar motion and Yin-Yang cycles confirms this: Kan (Water) corresponds to the moon's Wu-Earth luminosity, Li (Fire) to the sun's Ji-Earth radiance—their union forms the character "Yi" (change), blending firm and yielding. The central Wu-Ji Earth commands the seasons, harmonizing the four directional energies (blue, red, white, black), all relying on the middle palace (Dantian's) balancing function.

Between Heaven and Earth, positions are established, and the workings of Change (Yi) move within them. Here, "Heaven and Earth" symbolize Qian (Heaven) and Kun (Earth), while "establishing positions" refers to the pattern of Yin-Yang interaction. "Change" specifically manifests as the Kan (Water) and Li (Fire) trigrams, which embody the functional expressions of Qian and Kun. These two functions have no fixed positions among the six lines; they circulate through the six voids (the six directions of space), flowing without fixed paths, ascending and descending without constant form. Profound and hidden, they transform within formlessness, encompassing all things—this is the guiding principle of the Dao.

This passage explains how the subtle workings of Kan and Li are contained within the positioning of Qian and Kun. In the Zhouyi, the symbolic images of Qian and Kun are Heaven and Earth, while Kan and Li represent the sun and moon—these are the tangible, named manifestations of Qian, Kun, Kan, and Li in the post-Heaven world. Before Heaven, Earth, sun, and moon took form, the cosmos was a state of undifferentiated chaos, the Great Void of the pre-Heaven realm. Originally, this pre-Heaven Void contained nothing, perfectly round and radiant (pre-Heaven Qian); yet within it lay the undifferentiated primal Qi (pre-Heaven Kun), permeating and filling all space. From this Void emerged the supreme Yang Qi, within which lurked the austere supreme Yin (rising from Kun). The formless Great Void containing all potential is the Li image within Qian. From Qi condensed the supreme Yin essence (Jing), within which resided the manifest supreme Yang (descending from Qian). The tangible myriad things contain the formless root—this is the Kan image within Kun. The pivotal mechanism lies in the central axis between ascent and descent. When this axis stirs, Heaven and Earth separate: Heaven above, Earth below; the sun rises in the east, the moon appears in the west. Thus, in Fu Xi's pre-Heaven Bagua arrangement, Qian occupies the south and Kun the north (symbolizing Heaven above and Earth below encompassing all things—this is "Heaven and Earth establishing positions"), while Li is in the east and Kan in the west (symbolizing the sun and moon facing each other, water and fire interpenetrating Heaven and Earth). Yet only after Heaven and Earth take form can the functions of sun and moon manifest. Therefore, the Xici Zhuan states, "Heaven and Earth establish their positions, and Change moves between them"—a direct explanation. Wei Boyang (author of the Cantong Qi), concerned that people might misunderstand, clarifies: the "Heaven and Earth" here do not refer to external celestial phenomena but to the numinous, empty fundamental state of Qian and Kun (the "gateway" mentioned earlier); "establishing positions" does not mean physical locations but....

This passage explains the principle of interaction between the "Kan-Li" (water-fire) energies in Daoist Neidan (internal alchemy) practice. "Kan-Li" represents the yin and yang energies within the human body, circulating as naturally as the sun and moon move between heaven and earth.

The text points out that the single yin line within the Qian trigram (pure yang) transforms into the Li trigram (fire), while the single yang line within the Kun trigram (pure yin) becomes the Kan trigram (water). The Li trigram symbolizes the sun, rising in the east and setting in the west; the Kan trigram represents the moon, ascending in the west and moving eastward. This celestial dance mirrors the circulation of primordial Qi (vital energy) within the human body.

What's remarkable is that true water (yin) resides within the fire of Li, while true fire (yang) hides within the water of Kan. This state of "mutual containment between water and fire" generates countless transformative effects. The key to cultivation lies in grasping the profound mystery of yin-yang interaction—neither pure yin nor pure yang, but rather the "empty cavity" state where both merge. This principle forms the fundamental guideline for Dao cultivation.

Finally, it mentions that genuine practice transcends the realm of form and matter ("governing the substantial with the insubstantial"). By comprehending the waxing and waning patterns of yin-yang ("calculating growth and decline"), practitioners return the Kan-Li energies to their source ("the disappearance of Kan-Li"), achieving unity with the Dao. This requires regulating breath and other methods to allow the body's Qi to circulate naturally like a bellows ("tuoyue").

This passage explains the subtle functions of the Kan (Water) and Li (Fire) trigrams from the Bagua (Eight Trigrams) in cultivation practice. The Kan and Li trigrams have no fixed positions—they flow through all six directions like air. Though formless and shapeless, they encompass all things and embody the operating principles of heaven and earth. This perfectly illustrates how "non-being" governs "being"—just as Laozi said, when clay is kneaded into a vessel, it is precisely the empty space within that makes it useful.

Kan and Li control form through formlessness, with the key lying in their central emptiness. The transition from formless to form is called "growth" (Xi), representing the phase of Yang Qi expansion—like the Kun trigram (pure Yin) transforming three times to become the Qian trigram (pure Yang). The transition from form to formless is called "dissipation" (Xiao), marking the phase of Yin Qi receding—like the Qian trigram transforming three times to become Kun. Starting from the new moon, the Zhen trigram (symbolizing nascent Yang) activates, progressing through Dui to Qian; from the full moon, the Xun trigram (symbolizing nascent Yin) activates, progressing through Gen to Kun. Though Kan and Li appear invisible in this process, they continuously circulate through all six directions.

These theories are empirically verifiable. For example, the saying "the sun and moon form Yi (change)" combines the characters for "sun" (日) and "moon" (月) into "易" (Yi), symbolizing the transformations of Yin and Yang. The movements of the sun and moon indeed follow this pattern, proving these principles are not fabricated.

The passage then explains how the harmonization of Kan and Li Qi depends on the central "True Earth." The Kan trigram represents the moon, containing Wu Earth (Yang Earth), which originates from Qian—this is Yang Qi concealed within Yin, as the Daode Jing states: "dim and dark, yet within it lies the essence (Jing)." The Li trigram represents the sun, containing Ji Earth (Yin Earth), which originates from Kun—this is Yin Qi adhering to Yang, as described: "indistinct and hazy, yet within it lies substance." When solar light and lunar essence converge along the ecliptic, they form the Primordial Supreme Change (Taiji), precisely because Wu and Ji Earth harmonize in firmness and softness. Thus, "the sun and moon form Yi" symbolizes the balance of Yin and Yang, with Wu and Ji Earth acting like the central Earth Virtue (De) in the cycle of seasons—governing the four directions (east-green, south-red, west-white, north-black) and sustaining heaven and earth from beginning to end.

This scripture primarily discusses the correspondence between the Five Phases (Wood, Fire, Metal, Water, Earth) with the four seasons and directions, as well as the central role of "Central Palace True Earth" in cultivation practice.

Each of the Five Phases has its peak season and corresponding direction: Wood flourishes in spring, corresponding to the east; Fire thrives in summer, corresponding to the south; Metal peaks in autumn, corresponding to the west; Water dominates in winter, corresponding to the north. Earth permeates all seasons and occupies the center, governing the four directions. The Azure Dragon of the east belongs to Wood, the Vermilion Bird of the south to Fire, the White Tiger of the west to Metal, and the Black Tortoise of the north to Water - all these directional energies converge at the central Wuji Earth (a Daoist term referring to the yin-yang earth at the center).

The key to cultivation lies in harmonizing the Five Phases, causing Metal, Wood, Water and Fire to gather at the central "Yellow Center" position (referring to the Dantian), which enables the formation of the Great Elixir (the highest achievement in Neidan practice). The subtle functions of the Kan (Water) and Li (Fire) trigrams both rely on the harmonizing action of the central Wuji Earth - this constitutes the core teaching of the Cantongqi (The Seal of the Unity of the Three) classic.

The appended section mentions Master Tan's (Tan Qiao, a renowned Five Dynasties period Daoist) view: After the opening of heaven and earth, tangible earth appears, but during primordial chaos, earth transforms into emptiness - demonstrating earth's mysterious capacity for transformation between substantial and insubstantial states.

Finally, it discusses the symbolic meanings of the sun and moon: The sun contains the essential energies of the Five Phases, while the moon follows the patterns of the six ancient pitch standards - both serving as important symbolic references in the Yijing (Book of Changes). This passage was previously misclassified in another chapter but has now been corrected according to the canonical edition.

This passage elucidates the profound relationship between the movements of the sun and moon with the transformations of Yin and Yang, revealing the fundamental principles of alchemical practice (neidan).

First, it explains celestial patterns: A thirty-day cycle (six periods of five days each) completes one revolution. By observing this cyclical motion, one comprehends the mysteries of creation—when Yang Qi recedes, Yin Qi advances to take its place, like spokes of a wheel alternating in motion. The dual energies of Yin and Yang continuously transform between expansion and contraction. This resembles the 384 changing lines in the Book of Changes (Yijing), where each hexagram symbol (fu) corresponds to specific seasonal nodes, particularly during the new moon (shuodan) when thunder (the Zhen hexagram) first stirs, marking the cosmic intercourse of Heaven and Earth's Yin-Yang energies.

The text then describes alchemy's core principle: During this convergence, the essences of Heaven and Earth intermingle, with solar and lunar energies mutually attracting. The Yang force disseminates primordial energy (xiongyang bo yuanshi), while the Yin force gestates life's embryonic form (ciyin huang bao). In this undifferentiated state of chaos (hundun xiang jiaojie), the foundation for alchemical practice is established (quanyu shu genji). Like nurturing an embryo (jingying yang yin'e), through concentrated spirit (ningshen), the elixir body eventually forms (cheng qu). All life activities (zhongfu dao yi chu) and subtle movements (ruan dong) originate from this principle of Yin-Yang interaction.

The latter section focuses on interpreting the essence of "Change" (Yi): What we call "Change" manifests in celestial phenomena (xiang ye), with the sun and moon being its most prominent expressions. The sun contains the quintessence of the Five Phases (ri han wuxing jing), while the moon follows the rhythms of the six pitch-standards (yue shou liulv ji). Their significance lies in their paradoxical nature: The sun, though fundamentally a fire essence (taiyang huo jing), conceals true Yin (taiyin zhen shui) at its dark core, forming the Li hexagram's white exterior and black interior. Conversely, the moon, as a water essence (taiyin shui jing), harbors true Yang (taiyang zhen huo) at its luminous center, creating the Kan hexagram's black exterior and white interior. The moon itself emits no light (yue ben wu guang)—its radiance comes from solar reflection (shou ri ying chu ze you guang). Lunar phases directly manifest the sun's changing illumination (guang sheng yu ri zhi suo zhao, po sheng yu ri zhi suo bu zhao). This dynamic interplay during the moon's dark-to-new transition (huishuo zhi jiao) represents the critical timing for controlling the alchemical fire in practice.

This scripture uses the waxing and waning of the moon as a metaphor for cultivation principles. The moon itself does not emit light—its phases depend entirely on the angle of sunlight: when the moon lies directly beneath the sun, its earth-facing side remains completely dark (called "hui," the dark moon); at a 90-degree angle, we see a half-moon ("first quarter"); when opposite the sun, we witness the full moon ("wang," the full illumination); then it gradually wanes to the "last quarter" before returning to "hui."

The sun symbolizes humanity's innate luminous nature (xing), eternally unchanging, while the moon represents our postnatal life (ming), subject to impermanent transformations. The sun (ri) contains the quintessence of the Five Phases: its fiery nature (true solar fire) houses the golden crow (symbolizing water's essence), nourished by wood Qi to radiate golden light, all sustained by earth's De (virtue) in harmonious operation. The moon's (yue) movement corresponds to the twelve pitch standards (Huangzhong, Dalü, etc.), cycling from the new moon's (first day) nascent Yang Qi to the full moon's (fifteenth day) Yang culmination, then to the dark moon's (month's end) matured Yin Qi in perpetual rhythm.

Cultivation mirrors this cosmic cadence: one must recognize the impermanence of postnatal existence (like the moon's phases) and return to the indestructible radiance of innate nature (like the sun's constancy). The sun progresses one degree daily, while the moon moves over thirteen degrees, requiring approximately 29.5 days to realign with the sun—a cycle perfectly manifesting the natural law of Yin-Yang ebb and flow.

This scripture primarily elucidates the patterns of Yin-Yang transformation and the movements of the sun and moon. Among the ten Heavenly Stems, the number "six" represents the midpoint of Yin, and two sixes make up the twelve Earthly Branches. Five days constitute a hou (an ancient time unit), and six hou form one qi (solar term). Multiplying five by six yields exactly thirty days, aligning with the lunar cycle of waxing and waning. The moon cycles from hui (complete darkness) to shuo (new moon), xian (half-moon), and finally wang (full moon), repeating endlessly in an eternal rhythm.

The key to understanding these transformations lies in grasping the principle of mutual concealment within Yin and Yang. Superficially, the sun and moon appear as two separate celestial bodies, yet within the sun resides true Yin (called "true water"), and within the moon resides true Yang (called "true fire"). Though their movements seem alternating, the sun’s primordial Qi is hidden within the moon, and the moon’s essence is concealed within the sun. This mutual containment embodies the "divine mystery of Yin-Yang’s unpredictability."

The revolutions of the sun and moon resemble the turning of a wheel—their rising and setting create day and night, their opening and closing determine lunar phases, and within this lies the cycle of seasons, the shifts of heat and cold, and the ascent and descent of cosmic Qi. The human body also contains this fusion of solar and lunar essences, ultimately converging in the middle palace (Dantian) as the primordial spirit (Shen). Just as the Book of Changes unfolds through sixty-four hexagrams and three hundred eighty-four lines, during the transition between hui and shuo (the junction of the lunar month’s end and beginning), the vital energies of heaven and earth intermingle, and the two Qi of Yin and Yang unite—akin to the chaos of creation, from which all life emerges. This passage expounds the cosmic principle of Yang Qi arising ("the return of one Yang") during the conjunction of the sun and moon, illustrating how "the sun and moon embody change (Yi)" as the foundation of creation.

The sixty-four hexagrams of the Zhouyi (Book of Changes) correspond to the patterns of celestial movement. Excluding the four cardinal hexagrams of Qian (Heaven), Kun (Earth), Kan (Water), and Li (Fire) which represent the alchemical furnace, cauldron, and medicinal substances, the remaining sixty hexagrams with their three hundred and sixty lines perfectly match the three hundred and sixty degrees of the celestial sphere without the slightest discrepancy. Each hexagram has a primary line position—for instance, the Zhun hexagram's key line is at the initial position, while the Meng hexagram's is at the top position. In alchemical terminology, these primary lines are called "talismanic markers" (fu).

The moon's cycle between its dark and new phases (the end and beginning of the lunar month) mirrors the daily transition between the Hai (9–11 PM) and Zi (11 PM–1 AM) hours. During the convergence of these lunar phases, when the sun and moon meet in the celestial region of Xu and Wei (two lunar mansions in the northern quadrant), yin energy reaches its zenith while yang energy begins to stir. This corresponds precisely to the initial line of the Zhen hexagram, symbolizing the first stirrings of yang qi. At this moment, celestial yang descends into earthly yin, creating a cosmic embrace akin to the sun and moon enveloping each other—a manifestation of Heaven-Earth intercourse. The Qian (Heaven) releases authentic yang qi, while the Kun (Earth) receives and nurtures it with its profound De (Virtue). The fusion of these two energies forms an egg-like shape, returning momentarily to a state of primordial chaos.

Within this chaotic fusion emerges a "true seed" (the primal qi of the prenatal state), which serves as the foundation for alchemical practice. This seed obtained through the Kun hexagram must be carefully nurtured to gradually coalesce into form, allowing the original spirit (shen) to mature—just as the Zhen hexagram's initial line symbolizes the sprouting of yang qi. This true seed is not only the origin of human life but the fundamental essence of all living beings.

While nature follows this pattern to generate the myriad things, Daoist practitioners reversely apply it to cultivate the inner elixir (neidan). The juncture between the moon's dark and new phases represents the "living Zi hour" (the optimal timing for practice), where the convergence of yin and yang produces the "medicine" (the energy required for cultivation). The process of nurturing the true seed is key to consolidating the original spirit. The cyclical movements of the sun and moon embody the natural rhythm of yin and yang's waxing and waning.

This scripture elucidates the fundamental principles of Daoist Neidan (internal alchemy) practice and the patterns of celestial movements, presented in two sections:

The first section reveals that the essence of Neidan cultivation lies in harnessing the primordial True Yang Qi (the "primordial true seed"). Practitioners must establish their foundation by emulating the state of primordial chaos at the creation of heaven and earth, where the union of Yin and Yang (symbolized as the coupling of dragon and tiger) generates the Golden Elixir. The ascending dragon (Yang) rises to heaven bringing rain, while the descending tiger (Yin) enters the earth to produce metal—this harmonious interaction between heaven and earth symbolizes the primal fusion. By concentrating one's Shen (spirit) in the Dantian (energy center), the practitioner naturally achieves the Golden Elixir body. While external Yin-Yang union creates worldly procreation, internal Yin-Yang union enables return to the origin and attainment of longevity.

The second section employs the hexagrams of the Yijing (Book of Changes) and lunar phases ("celestial tallies") to explain the timing of alchemical practice. Confucius praised the primordial virtue of creation, using the "Guanju" poem to symbolize the initial interaction of Yin and Yang. The Fu hexagram represents the birth of Yang Qi, akin to an eldest son inheriting his father's legacy. The text details the correspondence between moon phases and the eight trigrams: the crescent moon appears at the Zhen trigram (Geng position) on the third day, the first quarter moon at the Dui trigram (Ding position) on the eighth day, the full moon at the Qian trigram (Jia position) on the fifteenth day, followed by waning phases—the last quarter moon at the Gen trigram on the twenty-third day, and complete darkness at the Kun trigram on the thirtieth day. The numbers seven and eight (representing Lesser Yang and Lesser Yin) total fifteen days, as do nine and six (Greater Yang and Greater Yin), perfectly matching the lunar cycle.

The conclusion emphasizes observing the Three Powers—celestial patterns (the River Chart), earthly principles, and human mind—ensuring all actions align with hexagram transformations. When rulers govern according to these rhythms, universal harmony prevails. Practitioners must likewise attune their cultivation to these astronomical cycles, engaging in practice at precisely timed intervals.

This chapter elucidates the cyclical patterns of celestial movement (Tianfu) and their waxing-waning transformations—precisely the principles governing fire-phasing (huohou, the rhythmic regulation of Qi during practice) in Golden Elixir (Jindan) cultivation.

Confucius (Zhongni) marveled: "During the primordial chaos (Hongmeng), the Virtue (De) of Heaven (Qian) and Earth (Kun) permeated the void. To investigate antiquity (Jigu), we begin with the era of the Primal Sovereign; the Book of Songs opens with 'Guanju,' narrating the origins of human coupling. When Yin-Yang energies intertwine, they resemble tender sprouts emerging in early spring."

Here specifically addresses the initiation of fire-phasing. The previous chapter mentioned the nascent Yang energy during lunar conjunction (between the last and first lunar days), particularly indicating the season for elixir formation. Yet the complete principles governing the Golden Elixir's fire-phasing rhythms remained unstated—only now are they fully revealed. The celestial Dao fundamentally operates through the Five Phases (Wuxing), while human affairs prioritize the Five Classics—mutually illuminating yet each having distinct origins. The Book of Changes (Yijing), chief among the classics, begins with the Qian and Kun hexagrams, which themselves emerge from the Supreme Ultimate (Taiji)—this primordial unity coalesces as the undifferentiated Hongmeng Qi when whole, and divides as the Qian-Kun duality when separated.

Heaven and Earth unite—their essence contains all transformations, their function connects with the void. Thus Confucius praised: "How magnificent is Qian's origin! How perfect is Kun's root!" Is this not precisely the genesis of Yin-Yang? When editing the Book of Documents, Confucius started with the canons of Yao and Shun, opening with investigations of antiquity; compiling the Book of Songs, he began with the "Zhou Nan" and "Shao Nan" sections, leading with "Guanju"; the Book of Rites emphasizes coming-of-age ceremonies, where capping and marriage rites initiate procreation; the Spring and Annals chronicles commence with "first year" temporal sequences. The immortal Wei Boyang (Xianweng) employed these classical references to analogize cultivation methods.

Hongmeng signifies the Qi of emptiness. Qian symbolizes the cauldron containing the root of spiritual nature (Xing), while Kun represents the furnace harboring the foundation of vital life (Ming). Between them, the sun and moon traverse, manifesting the void's interconnectedness. The Primal Sovereign metaphorizes the original ancestral Qi (Yuanshi Zuqi); "Guanju" illustrates the mutual resonance of Yin-Yang substances; "intertwining" depicts the coupling of dual energies; "first-year sprouting" analogizes the initial stirrings of Yang energy when the true seed (elixir embryo) begins germinating.

Sages (here referring to the Yijing's authors) never theorized arbitrarily—they observed celestial patterns revealing cosmic principles (Tianfu). These heavenly correspondences advance, retreat, contract and extend in seasonal harmony. Thus the Book of Changes comprehends the cosmic heart (Tianxin), with the Fu hexagram (Earth over Thunder) symbolizing Yang's first stirring—like an eldest son inheriting his father's work, establishing foundations through the maternal matrix. Yin-Yang fluctuations must accord with musical harmonics; Qi's ascent-descent follows the Northern Dipper's revolutions.

This passage unequivocally identifies the nascent Yang's return (Yiyang Laifu) as elixir cultivation's foundation. Through observing celestial patterns like solar-lunar conjunctions, sages revealed the fundamental principles of Golden Elixir practice.

This passage explains the principles of Yin-Yang transformation in alchemical practice (Neidan cultivation). The previously mentioned "adjusting methods according to hexagrams" manifests in the rhythm of advancement and withdrawal during Daoist cultivation: From the new moon (beginning of lunar month) to the full moon, this is the phase of Yang energy growth, corresponding to the six two-hour periods from midnight (23:00-1:00, Zi hour) to mid-morning (9:00-11:00, Si hour), when Yang expands while Yin contracts. From full moon to month's end, this is the phase of Yin energy growth, corresponding to noon (11:00-13:00, Wu hour) to late evening (21:00-23:00, Hai hour), when Yin expands while Yang contracts. All movements and stillness in cultivation must follow this natural rhythm.

The Yinfu Jing (Scripture of the Hidden Talisman) emphasizes the importance of observing celestial patterns and grasping the laws of temporal cycles. The sun-moon interactions of celestial Dao produce the advance and withdrawal of Yin-Yang, which Neidan practice emulates. The essence of "Yi" (change) manifests in the movements of sun and moon, all governed by the "Heavenly Heart" (Tianxin) - the core law of the cosmos. This Heavenly Heart is the sovereign of creation, equivalent to Taiji (Supreme Ultimate) - the formless prenatal Taiji generates heaven and earth, while the postnatal Taiji propels the operation of the manifest world.

In the heavens, Tianxin corresponds to the midpoint between celestial poles; in the human body, it's the convergence point of the Kan (Kidney) and Li (Heart) trigrams. The union of Kan and Li constitutes the changes of Yi, all unified at the center of heaven and earth. Tianxin itself transcends movement and stillness, yet its function manifests at the transition between Hai and Zi hours (23:00-1:00) when stillness and motion alternate. When all things reach perfect stillness - like the sun and moon conjoining or constellations pausing - Tianxin becomes utterly traceless. At the extreme of emptiness and stillness, something emerges from nothingness: pure Yang Qi (primordial energy) bursts forth from utmost Yin, establishing the foundation for alchemical work.

Confucius remarked in the Yijing (Book of Changes) that the Fu hexagram (Earth over Thunder) reveals the heart of heaven and earth, while Shao Yong's poetry describes the winter solstice's Zi hour as Tianxin's immutable moment - both referring to Fu hexagram symbolizing life's germination. Fu's inner trigram Zhen (Thunder) with one Yang line inherits Qian's (Heaven) initial Yang; though rooted in Qian, it requires Kun's (Earth) nourishment, like an embryo developing in the womb. This nascent Yang energy grows gradually, corresponding musically to the Huangzhong tone (first of twelve pitch standards), while the Big Dipper's handle points due north, signaling Yang's initial ascent.

This passage explains the Daoist Neidan (internal alchemy) practice of using lunar phases to regulate the "fire times" (metaphorical heating stages) in cultivation. Ancient practitioners correlated the moon's cycles with the Bagua (Eight Trigrams) and heavenly stems, creating a guidance system called "Najia" (matching the trigrams with the ten celestial stems).

When the crescent moon first appears in the western Geng position on the third day of the lunar month, the Zhen trigram (representing thunder) pairs with Geng, symbolizing the initial emergence of Yang energy. This mirrors how the alchemical cauldron begins warming slightly during practice, as the practitioner's innate primordial nature (original spiritual essence) starts manifesting. This is what the text refers to as "on the third day, light first appears, with Zhen trigram matching Geng position in the west."

By the eighth day, the first quarter moon appears in the southern Ding position, where the Dui trigram (representing lake) pairs with Ding, showing balanced Yin-Yang energies. Like the furnace fire growing stronger in alchemy, practitioners perceive their spiritual light penetrating bodily obstructions. The text describes this as "on the eighth day, Dui trigram matches Ding position, the first quarter moon hangs level like a taut string."

At full moon on the fifteenth day, the moon in the eastern Jia position pairs with Qian trigram (representing heaven), marking complete Yang perfection. This resembles the alchemical process reaching its peak, with practitioners' spiritual nature fully revealed and inner illumination shining ceaselessly. The imagery of "on the fifteenth day, Qian trigram achieves perfection, matching Jia position in the east" captures this. The text's mention of the "toad" (moon) uniting with the "hare's essence" (lunar shadows) symbolizes the merging of solar and lunar essences.

This method divides the lunar month into six phases (3rd, 8th, 15th, 16th, 23rd, and 30th days), each corresponding to specific trigrams and directions to guide fire regulation. Just as the winter solstice marks the year's Yang rebirth, each new moon (shuo day) begins a new alchemical cycle when sun and moon unite in undifferentiated Yin-Yang harmony—the optimal time for practitioners to collect their Shen (spirit) and return to primordial origins.

Here, the toad and jade rabbit symbolize the mysteries of celestial motion. The toad (representing the sun) lurks beneath water, absorbing the golden essence of sunlight through its breath—mirroring how the sun transmits energy to the moon. Earthly rabbits, all female, become pregnant by gazing at the lunar rabbit, birthing offspring from their mouths—a metaphor for the moon receiving solar radiance before releasing energy from within.

The sun (Li trigram, positioned at Si) embodies expansive energy emission, while the moon (Kan trigram, positioned at Wu) embodies transformative reception. The sun bestows while the moon unfolds its glow. During the waning moon to new moon phase, the moon appears in the western You position, fully absorbing solar essence; from waxing moon to full moon, it brims in the eastern Mao position, wholly manifesting solar brilliance.

These creatures were chosen deliberately: the toad represents focused absorption through stillness, the rabbit exemplifies rhythmic expulsion and regeneration. Lunar phases depend entirely on solar reception—when Yin energy arises in the Xun position (southeast), moonlight gradually withdraws until vanishing completely, revealing creation’s inner mechanism; when Yang energy emerges in the Zhen position (east), moonlight expands to fullness, displaying creation’s outward manifestation.

At new moon, sunlight merges with the lunar essence (po) through resonant communion. By the third lunar day, faint light reappears in the western Geng position, journeying eastward from Geng to Jia until achieving perfect roundness on the fifteenth day. Post-full moon, Yang culminates and transforms—solar fire yields to lunar seal (contractive phase). After the sixteenth day, Yin dominates while Yang recedes. By the twenty-third day’s waning moon, lunar essence ascends as solar spirit (hun) wanes, with moonlight glowing in the southeastern Bing position while the Gen trigram (northeast) absorbs Bing’s energy, forming dual-Yin stillness.

This passage explains the correspondence between the waxing and waning of Yin-Yang in Daoist Neidan (internal alchemy) practice and the lunar phases, employing the Bagua (Eight Trigrams) from the Book of Changes and the celestial stems (Jia, Yi, etc.) as metaphors for energy transformation during cultivation.

When the moon enters its waning phase (23rd to 30th day of the lunar month), it corresponds to the Gen trigram (symbolizing mountain), where Yang Qi gradually diminishes. At this stage, Yin energy (Kun, the Earth) becomes dominant—like losing companionship in the northeast direction—as Yang energy completely withdraws into Yin. This state is called "nature returning to life" (xing fan wei ming), where one's primordial nature reverts to the source of life, as if Yang Qi has returned to the undifferentiated chaos before creation.

Yet Yang energy never completely disappears. Just when the moon reaches its darkest point, a new lunar cycle begins. The Zhen trigram (symbolizing thunder) inherits energy anew from Qian (heaven) and sprouts again within Kun's (earth) maternal embrace. In the western direction (corresponding to celestial stem Geng), the new moon's light reappears—demonstrating the cyclical alternation of Yin and Yang.

The phrase "Ren and Gui pair with Jia and Yi; Qian and Kun encompass the beginning and end" refers to the correspondence between celestial stems and trigrams: Kan corresponds to Wu, Li to Ji, Zhen to Geng, Xun to Xin, Gen to Bing, Dui to Ding. Qian corresponds to Jia and Ren, while Kun corresponds to Yi and Gui—thus encompassing the energetic transformations of the other six trigrams.

Numerologically, the numbers of lesser Yang and lesser Yin (young male and female) are seven and eight respectively, summing to fifteen—the same as the sum of greater Yang and greater Yin (Qian and Kun) being nine plus six. This perfectly matches the complete cycle between lunar quarters. From new moon to full moon represents Yang growth and Yin decline; from full moon to dark moon shows Yin growth and Yang decline. When Yang seems utterly vanished, the fundamental primordial Qi actually remains concealed within emptiness, awaiting the new cycle.

Through lunar imagery, this text vividly illustrates the principle of ceaseless Yin-Yang transformation in Neidan practice, emphasizing that even when energy appears absent, it merely transforms into latent potential preparing for the next cycle.

This passage elucidates the principles of discerning the "fire timing" (huohou) in Golden Elixir (Jindan) cultivation through observing the transformations of Yin-Yang. The cyclical movements of heaven and earth, the alternation of sun and moon, and the distribution of the Eight Trigrams (Bagua)—Qian (Heaven), Kun (Earth), Zhen (Thunder), Xun (Wind), Kan (Water), Li (Fire), Gen (Mountain), and Dui (Lake)—all follow the waxing and waning patterns of Yin and Yang. Though the positions of Kan and Li trigrams may not be visibly apparent, the ascending and descending Qi of Yin-Yang throughout the six directions (up, down, and the four cardinal points) is precisely propelled by the harmonizing energy of these two trigrams. The celestial motions of sun and moon symbolize Yin-Yang transformations, governing the core dynamics of the cosmos and serving as the standard for the advance and retreat of the three Yin and three Yang phases.

The subtlest primordial essence (Yuanyuan Jing), as the foundational energy of life, cannot be directly observed but must be verified through celestial phenomena. Practitioners should calmly study natural rhythms to establish precise benchmarks for discerning auspicious and inauspicious timings—akin to using gnomon measurements to track solar shadows or divination to determine seasonal nodes. When the "fire timing" has not yet arrived, one must wait in stillness. At the moment when Kan and Li energies intersect, a drop of primordial essence spontaneously emerges—this is the "true seed of the primordial" (Xiantian Zhenzhong), the fundamental basis of cultivation, profoundly mysterious yet undeniably real.

This refined energy is so exquisitely subtle that ordinary perception cannot grasp it directly; its movements can only be inferred through lunar phases and other celestial patterns. The advance and retreat of heavenly Dao leaves no physical traces—one must carefully contemplate its workings within emptiness, meticulously discerning the shifts between Yin's recession and Yang's growth. As the critical moment approaches, responsiveness must be as precise as an astronomer measuring solar shadows or a diviner determining fortunes, especially during the liminal space between the moon's disappearance and reappearance (huishuo), when Yang energy is about to emerge but not yet manifest, when movement and stillness hang in balance.

When the pivotal moment of Yin-Yang transformation arrives, practitioners must act with the timely decisiveness of imperial edicts being issued or seasonal nodes being fulfilled by heaven and earth. The "timing" referenced here corresponds to the "living midnight hour" (huo zishi) described in the Scripture of Hidden Correspondences (Yinfu Jing)—specifically that fleeting, subtle instant between the moon's waning and waxing phases.

At the winter solstice when yang qi first emerges, this pivotal moment is called "true midnight hour" (zheng zishi). Practitioners must observe celestial phenomena above (represented by the Hetu's cosmic cycles), examine terrestrial patterns below (symbolized by the Luoshu's geographical orientations), while simultaneously attuning to the fluctuations of human consciousness in between—thus correlating the operational principles of Heaven, Earth and Humanity, the Three Powers (sancai).

The cosmos operates through dynamic and static phases: Qian (Heaven) above and Kun (Earth) below form the fundamental pattern, while the qi mechanisms of Kan (Water) and Li (Fire) circulate between them, representing humanity's intermediary position. This pulsation of movement and stillness permeates creation, encapsulating the profound mysteries of both the Hetu and Luoshu diagrams.

The Hetu's fifty-five numerical cycles embody celestial dynamism, whereas the Luoshu's nine-palace arrangement reflects terrestrial stability. Human consciousness, positioned between motion and stillness, becomes the crucible of cosmic transformation. When acting in harmony with celestial timing, one follows the hexagram lines' rhythmic changes ("movement follows gua patterns"); when quiescently aligned with earth, one adheres to the judgments' guidance ("stillness accords with tuan phrases").

Neidan cultivation pivots on mastering yin-yang alternation: When stillness culminates in movement, pure yang qi ascends from the nine heavens (called "Qian's primal yang activation"), elevating the original spirit (shen, innate awareness) to the crown (the Qian cauldron). When movement resolves into stillness, pure yin qi descends to the nine earths (termed "Kun's primal yin application"), returning primordial qi (vital energy) to the lower dantian (the Kun furnace). Shen manifests our true nature while qi sustains life—when dual cultivation of nature and life (xingming shuangxiu) reaches fruition, the Celestial Heart (cosmic origin) spontaneously reveals itself.

This passage elucidates the core principles of cultivating the Golden Elixir (Jindan), employing cosmic movements and state governance as metaphors for spiritual practice.

The text begins by comparing the human body to a microcosm, where all bodily joints and myriad spirits (referring to physical components and internal energies) converge toward the center like spokes in a wheel. This mirrors the Dao of heaven and earth, where the interaction of Qian and Kun (symbolizing Yin-Yang and cosmic polarity) permeates all existence. Earlier chapters established Qian and Kun as the gateway to the Yijing (Book of Changes), while this section further clarifies that once cosmic positions are established, the movement of Yin-Yang Qi flows as naturally as a door opening and closing.

The text then uses Kan and Li (representing the water and fire trigrams) to illustrate cultivation's pivotal mechanism. Just as a wheel requires an axle to rotate, practitioners must master the principle of "water and fire complementing each other" (huoshuijiji). While previous passages treated Kan-Li as practical applications of Qian-Kun, here it explicitly states that the movement of sun and moon (symbolizing Yin-Yang Qi) must maintain wheel-like equilibrium without deviating from the center.

Two extraordinary images appear: the "toad" (chanchu) representing metallic Qi essence that waxes and wanes with lunar phases, and the "jade rabbit" (yutu) symbolizing wood-essence brilliance that radiates during full moon. These archetypes originate from the ancient Hetu-Luoshu diagrams and the Prenatal Bagua arrangement, constituting the most profound elements of the Cantongqi (Kinship of the Three) and embodying the essence of Fuxi's Yijing wisdom.

Chapter Five employs statecraft as an alchemical metaphor: just as governance requires prudent administration, cultivation demands precise fire regulation (huohou). Like an emperor commanding officials, the "bright hall" (mingtang, representing heart-mind) must remain upright to facilitate the body's natural Qi circulation. Should the sovereign (symbolizing Shen/spirit) become arrogant or ministers (representing Qi channels) stray from their paths, danger arises. Celestial phenomena like the "five planets" (wuwe) and "twenty-eight constellations" (siqi) metaphorically depict internal Qi transformations. Practitioners must emulate wise rulers by mastering pivotal mechanisms and orchestrating holistic harmony between Yin-Yang energies within.

This section particularly emphasizes that cultivation requires governance-like rigor—the heart-mind must maintain the clarity and integrity of an enlightened ruler to avoid the perils of deviation (zouhuo rumo, literally "walking fire entering demonic states").

This passage employs the metaphor of imperial governance to illustrate the regulation of firing techniques in alchemical practice, emphasizing the need for exceptional caution in the initial stages of cultivation. Just as a newly enthroned ruler must exercise particular care in governance, the practice of the Golden Elixir (Jindan) path—the core method of Daoist internal alchemy (Neidan)—demands meticulous attention from the very beginning.

The text explains that the essence of cultivation lies in grasping the "Celestial Heart" (Tianxin, referring to the innate primordial spirit within the human body), much like how an emperor commands his ministers. When a practitioner begins their cultivation, the initial stirring of Yang Qi within the body is likened to a new ruler ascending the throne and proclaiming a new era. The "handle of the Dipper" (Kuibing) mentioned here refers to the handle of the Big Dipper, which ancient Chinese believed functioned as the celestial pivot, governing the movement of all stars—just as the main rope controls a fishing net or a button secures a garment.

The author uses celestial imagery to illustrate cultivation: the stars in the sky are divided into the Three Enclosures (Sanyuan: the Purple Forbidden, Supreme Palace, and Heavenly Market enclosures), the Five Planets (Wuxing: Venus, Jupiter, Mercury, Mars, and Saturn), and the Twenty-Eight Lunar Mansions. The North Star acts as the sovereign, with all other stars following its command. If the Dipper moves correctly, the stars remain orderly; if it deviates, the entire celestial arrangement falls into chaos.

Similarly, if the "Celestial Ruler" (Tianjun, the mind-spirit) within the human body becomes agitated, it leads to disharmony among the senses and disorder in Qi and blood. The passage underscores that cultivation must emulate the way a wise ruler governs a state or the Dipper regulates the stars—keeping the mind-spirit clear and upright to ensure the practice remains free from deviation. Quoting the Book of Changes (Yijing), it states that internal changes in the hexagram lines manifest as external signs of fortune or misfortune, demonstrating the interconnectedness of inner and outer realms.

This passage explores the analogical relationship between cultivating the Golden Elixir (Neidan, the Daoist practice for attaining longevity) and governing a nation.

Just as the slightest deviation in celestial movements prevents the formation of the elixir, a ruler cannot blame ministers for failures in state governance if their leadership is improper. The heavens mirror human administration: the Wenchang Star (overseeing scholarly honors and official ranks) corresponds to the Six Ministries, while the Taifu Stars (the Three Platforms and Four Supports in the Purple Forbidden Enclosure, symbolizing ministerial aides) represent the chancellor and high officials. The chancellor assists the ruler in harmonizing Yin-Yang, and the Six Ministries perform their duties—just as in alchemical practice, the Shen (spirit) maintains central control, ensuring the natural balance of Water and Fire (the body’s Yin and Yang Qi), allowing the meridians to flow unimpeded.

Both governance and alchemy demand unwavering vigilance. If a ruler grows arrogant and strays from the Dao, ministers will turn treacherous, much like irregular lunar phases herald calamities. A wise sovereign, like the North Star, must anchor himself in uprightness and govern with calm assurance to ensure stability. Similarly, the "fire times" (the precise regulation of intention and breath during practice) in alchemy require meticulous attention—the slightest misstep undoes all progress.

The passage emphasizes the sovereign role of Shen: just as ministers obey the ruler, the body’s Qi follows the will. When the spirit remains upright, external temptations cannot intrude; when it becomes reckless, the senses descend into chaos. Celestial phenomena resonate with the human heart—a minor deviation in the "Heart of Heaven" (cosmic order) disrupts stellar movements. Not only would the Five Planets (Wood, Fire, Earth, Metal, Water) stray from their paths, but even fixed stars would manifest anomalies.

This scripture employs the metaphor of court governance to illustrate the principles of Neidan (internal alchemy) practice. The moon follows its inherent cycle (with phases like new moon, first quarter, full moon, and last quarter), but if it waxes when it should wane or wanes when it should wax—manifesting abnormal celestial phenomena (eclipses or obscured brilliance)—countless calamities will ensue. In the celestial realm, the Taiwei Enclosure (a heavenly division) has the Left and Right Law Officials (constellations) overseeing faults, just as the imperial court appoints left and right censors. Yet the true fault lies not with the officials, nor even with the prime minister, but with the ruler themselves—emphasizing that the root of all things rests in cultivating one’s innate nature.

The scripture states that the effectiveness of the censors’ admonitions hinges on a single shift in the ruler’s intention. If the ruler (symbolizing the heart-mind) can maintain clarity, Wuwei (non-action), and steadfast adherence to the Dao, it is like the North Star remaining unmoved at the center while all other stars revolve around it, or like an emperor seated in the Mingtang (an ancient hall for proclaiming governance), where the world naturally submits. Here, the "Polar Star" (Chenji) symbolizes the abode of the heart-mind, while the "Mingtang" corresponds to the Tianshi Enclosure (another celestial division), representing the communication between the heart-mind and the external world.

The author draws precise parallels between statecraft and Neidan practice: the ruler represents the practitioner’s original mind, ministers symbolize the medicinal ingredients (Jing-essence, Qi-vital energy, and Shen-spirit) for alchemy, the Wenchang and Taifu constellations (celestial officials) correspond to the three Dantian (upper, middle, and lower energy centers) in the body, censors embody the sensory faculties, and officials represent the vital energies throughout the body. Auspicious or inauspicious outcomes depend on correctly mastering the "firing times" (refining techniques), with the key lying in resisting external distractions and safeguarding the inner true nature. If the heart-mind remains as steady as the North Star, all energies will naturally gather in the Mingtang—this is the essential method for returning to the origin and attaining the Dao.

This section of Can Tong Qi Chan You primarily elucidates the fundamental principles and concrete methods of cultivation. It begins by establishing Heaven and Earth (Qian and Kun, symbolizing Yin-Yang) as the foundation of practice, then explores the dynamic interplay between the Kan and Li trigrams (representing Water and Fire) as the crux of alchemical work. Subsequent passages describe how the convergence of Yin and Yang during the lunar phases of Hui and Shuo (the dark and new moons) generates the "medicinal substances" (referring to the essential Jing and Qi required for cultivation), and how practitioners must regulate the "fire times" (mental focus during practice) in accordance with celestial cycles—principles that mirror the governance of a state.

Just as the North Star governs the celestial sphere and an enlightened ruler administers officials, in internal cultivation, the human spirit (Shen) must command the vital essences (Jing-Qi) throughout the body. This is the meaning of "governing affairs" (Yu Zheng) in alchemical terms.

The middle section dedicates three chapters to "nurturing innate nature" (Yang Xing). Here, the primordial ancestral nature (humanity's inherent pure essence), though quiescent and unmoving, resonates with all phenomena. Residing in the Central Yellow Court (the middle Dantian, the cardiac region), it serves as the sovereign of life. During this cultivation, original essence (Yuan Jing) and primordial Qi (Yuan Qi) both return to embrace the original spirit (Yuan Shen, the innate luminous awareness). Only those who comprehend this practice align with the Dao of emptiness and spontaneity transmitted by the Yellow Emperor and Laozi. Hence, the concluding portion is termed "The Yellow Emperor and Laozi's Method for Nurturing Nature."

Chapter Six, "Refining the Self to Establish the Foundation," details the foundational work of cultivation. Practitioners must maintain inner stillness and emptiness, turning awareness inward to observe the body while "closing the sensory gates" (blocking external distractions) to stabilize the spiritual root (life's foundation). Through internalizing the Three Lights (Jing, Qi, and Shen), one incubates the inner elixir (the nascent pearl). Though seemingly formless, this practice permeates daily existence. When the Central Yellow Court (the nature-nurturing center) becomes unobstructed, it gradually nourishes the skin and flesh. Cultivation requires unwavering constancy—a truth most worldly people fail to grasp.

A key emphasis here is that "refining the self" (Lian Ji, tempering one's nature) constitutes the foundational practice. While earlier sections address the grand principles of cosmic Yin-Yang, this passage specifically directs practitioners to begin with self-refinement. As Lü Dongbin taught: "To forge the inner elixir, first refine the self while awaiting the proper timing." Similarly, Zhang Ziyang noted that achieving the ninefold-cycled golden elixir (Jindan) requires prior cultivation of one's nature. The "self" (Ji) corresponds to the Ji Earth within the Li trigram (symbolizing the nature-nurturing aspect)—the very root of both innate nature (Xing) and vital life (Ming).

This passage elucidates the core principles of "refining the self" (lianji) in Daoist cultivation. The pure Yang energy of our innate nature (qianxing) transforms into conscious activity (shishen) in the conditioned state, while the Yin qi in the heart constantly fluctuates, making it difficult to control. This must be balanced by the primordial Yang qi from the kidney water (the supreme innate qi within kan). Yet this primordial energy originates from the realm of emptiness—without the practice of quieting the mind (zhi xu shou jing), one cannot return to the source.

Every person is born with a luminous innate nature (a spark of spiritual clarity), but due to the disturbances of worldly desires, consciousness chases outward, mistaking illusion for reality. The key to cultivation lies in withdrawing the senses (shoushi fanting), turning the luminous nature inward without outward leakage. Through inner observation (neiguan), one realizes the illusory nature of the physical body, thereby attaining liberation. The orifices such as the mouth and nose (dui) are gateways through which primordial qi leaks. One must seal the heart-mind (huangting), where the vital energy of life's origin (lingzhu) is stored.

The human body mirrors celestial phenomena: the heart (li) resembles the sun, the kidneys (kan) the moon, and the celestial heart (dantian) the North Star. Through the union of water and fire (kan-li convergence) and inner contemplation, the true Yang (zhenren) can be concealed in the depths, preserving the primordial qi (yuanzhu). During cultivation, one may experience the vision of the "three lights descending into obscurity," requiring the gentle nurturing of the energy in the dantian (zizhu). That spark of spiritual radiance is actually close at hand, yet people constantly seek it externally.

In the early stages of practice, one must unblock the central channel (huangzhong) so that qi flows smoothly, nourishing the entire body. Only when the foundation is properly established (chuzheng) can subsequent cultivation be stable. These principles may seem simple, yet they are often overlooked by the world. The Scripture on the Salvation of Humanity (Durenjing) states that harmonizing the qi of the five viscera (wuqi) leads to the state of unity between heaven and humanity. The entire cultivation process hinges on holding fast to the primordial qi (de yi), returning to the origin through the practice of stillness and stability.

This scripture elucidates the core principles of Daoist Neidan (internal alchemy) practice. The so-called "Central Yellow Danjiong" (referring to the Dantian at the body's center) functions like the North Star, serving as the focal point where all bodily energies converge. Practitioners begin by gently nurturing the inner elixir (the "seed pearl") within this center, maintaining a natural state without forced striving. Over time, this process naturally leads to communion with the divine. When the practice matures, all nine orifices, meridians, joints, and even pores throughout the body will become unobstructed, causing the entire person to radiate brilliance—just as the Book of Changes describes inner beauty naturally manifesting through the limbs.

The cultivation process has initial and advanced stages, much like a tree has its trunk (the root) and branches (the tips). The most crucial aspect is ensuring the first step of entry is correct, as proper beginnings directly determine ultimate attainment. This fundamental principle is the "One"—humans take form before birth by receiving this "One," and after birth, maintaining this "One" enables elixir refinement. Following the "One" to generate all things is the natural order, while reversing course to return to the "One" constitutes the path of immortality.

As Laozi stated, "Attaining the One completes all endeavors." This "Valley Spirit" (referring to the primordial Shen) is seemingly empty yet brimming with numinous vitality, capable of unceasing generation. Its profound mystery lies in the phrase "conceal and obscure": concealing the Yuan Gate (the portal of primordial nature) and obscering the Feminine Opening (the aperture of postnatal existence). Without guidance from an enlightened teacher, even the wise like Yan Hui or Min Ziqian would struggle to comprehend these subtle mechanisms, let alone ordinary people. Thus, the scripture emphasizes understanding the location of the "Yellow Center" (Dantian) and the essence of the "One"—only by grasping this core can one truly begin the journey.

This passage elucidates the essential method of Neidan (internal alchemy) practice, focusing on mastering the dynamic interplay between the "Kan" and "Li" cavities within the human body.

It begins by stating that understanding the mysteries of the body's cavities reveals one's original innate nature, leading to comprehension of "guarding the center and embracing the One" (maintaining physical-mental equilibrium and focused unity). This constitutes the foundational practice of cultivating heart-mind nature.

The text employs the metaphors of "upper De (Virtue)" and "lower De": those with upper De practice Wuwei (non-action) naturally without deliberate pursuit, while those with lower De engage in continuous active effort. When the upper cavity (Li Palace, representing heart-mind Shen) closes, it manifests "presence"; when the lower cavity (Kan Palace, representing kidney Jing) closes, it manifests "absence." This "absence" nourishes the upper cavity where divine consciousness resides. These two cavities emulate and coordinate through the primordial Qi of metal.

White symbolizes the essence of metal (original Shen), black represents the foundation of water (original Jing). Water serves as the pivot of the Dao, numerically represented as one—the origin of Yin-Yang containing the "yellow sprout" (germination of primordial Qi). Like lead ore appearing black yet containing golden quality, the mystical state of realized beings (zhenren) exists between presence and absence, like objects floating and sinking in deep waters. During practice, Shen and Qi must return to their respective positions: Shen above and Jing below.

The text describes the alchemical phenomenon: within the square-inch Dantian (energy center), Shen and Qi intermingle. This pivotal region existed before heaven and earth's formation—majestic and revered, protected by barriers against invasive pathogenic energies. Practitioners must maintain naturalness without excessive mental exertion. When Shen-Qi becomes abundant, no deliberate control is needed; maintaining this state brings prosperity while losing it leads to decline. All movement and stillness must harmonize with the Dao.

Ultimately, this chapter directly reveals that applying the Kan-Li cavities constitutes the golden key to Golden Elixir cultivation. The Great Dao requires both the unity of "One" and the dynamic interaction of "Two." The previous chapter discussed "attaining the One" (grasping the root), while this chapter explains the practical application of "dual cavities." The Golden Elixir's mystical function manifests through post-heaven Kan-Li interaction, yet their mystery originates from pre-heaven Qian-Kun (Yin-Yang) harmony. Fundamentally, this revolves around "nature and life": nature (original spiritual light) represents the empty true essence, complete and flawless; life (primordial Qi) embodies wondrous function, manifesting according to conditions. Their union forms the foundation of the Golden Elixir path.

This passage explains the Daoist cultivation concepts of "Upper De (Virtue)" and "Lower De." "Upper De" refers to one's original nature before birth (innate disposition), which is pure and untainted, transcending worldly concerns and requiring no deliberate pursuit. If one obsessively tries to comprehend it through intellectual thought, one actually moves further away from it. Because this nature exists spontaneously and cannot be artificially contrived, consciously seeking it means failing to find it—hence the saying "Upper De is Wuwei (non-action)."

"Lower De," on the other hand, refers to the wondrous function of the ancestral Qi (primordial life-force energy) after birth. It sustains the triad of Heaven, Earth, and humanity, encompassing all phenomena. In Heaven, it manifests as the nurturing Kunyuan energy that nourishes all things; in humans, it is the foundation of life established by the first cry at birth. This primordial Qi circulates endlessly, transforming infinitely, but if one fixates on a state of empty stillness, it leads to lifeless stagnation. Because life requires movement—once circulation stops, death ensues—it is said that "Lower De acts, its function never ceasing."

When Kun (the yin principle) enters Qian (the yang principle) to form the Li trigram, the originally pure Upper De transforms into the active Lower De. People often mistake the emptiness at the center of the Li trigram for true void, when in fact this very emptiness is the wondrous existence within true emptiness, called "presence within absence." Conversely, when Qian enters Kun to form the Kan trigram, Lower De returns to the Wuwei state of Upper De. People often mistake the solidity at the center of the Kan trigram for wondrous existence, when in fact this very solidity is the true void within wondrous existence, called "absence within presence."

After Kun receives Qian's energy, it returns this genuine yang to Qian—this is the process of returning to the origin and recovering one's innate destiny. At this stage, an indestructible Yuanshen (primordial spirit) called the "Yin'e" forms within the innate divine chamber, representing the eternal, imperishable nature. The phrase "the formless offers itself upward" refers to the practice of refining Jing (essence) and Qi so they ascend, ultimately achieving a divine state. The key to cultivation lies in raising the genuine golden Jing from the Kan trigram to unite with the genuine watery Qi of the Li trigram, thereby attaining the harmonious fusion of yin and yang.

This passage elucidates the core principle of "gold within water" (primordial Qi) in Daoist Neidan (internal alchemy) practice. When the two energies of Yin and Yang—represented by Kan (Water/kidneys) and Li (Fire/heart)—intermingle, the Shen (spirit, or primordial awareness) naturally manifests. The "two apertures" mentioned refer to these crucial bodily cavities corresponding to Kan and Li, which the Daode Jing describes as the "Mysterious Feminine Gate" (the root of life).

The scripture emphasizes the essential practice of "knowing the white yet guarding the black": white symbolizes the golden Jing (essence, or primordial nature), while black represents the watery foundation (primordial Qi). Practitioners must understand that this "white" isn't physical metal but the pure original nature before cosmic formation, and "black" isn't ordinary water but the primal energy arising from emptiness. This innate golden quality, concealed within water, serves as the source of Yin-Yang energies and is symbolically called "yellow sprout" (representing gold hidden in water).

The crux of cultivation lies in maintaining a state of emptiness (Wuwei, non-action) during meditative stillness while preserving this point of primordial Qi within the body. This simultaneous "preserving emptiness and guarding substantiality" enables the instantaneous transformation from conditioned existence back to primordial origin. The "Northern River Chariot" (celestial orbit circulation) carries what appears to be ordinary lead (symbolizing primordial Qi), yet within it lies concealed precious gold—the external appears coarse ("clad in coarse cloth") while internally it holds jade. This constitutes the fundamental principle of the Golden Elixir path: by harmonizing Kan and Li and mastering Yin-Yang, the luminous Shen naturally reveals itself.

The Primordial Qi (the universe's most fundamental energy) resembles the pure Yang golden essence symbolized by the Qian hexagram. It governs the generation and transformation of all things, serving as the foundational force behind the formation of the later Five Phases (Metal, Wood, Water, Fire, Earth). This energy lies concealed within the Great Abyss of the North Pole (a metaphor for the lower Dantian in the human body), known as the "Sovereign of Five Metals" and the "Northern River Chariot."

Here, the five metals of external alchemy (silver, lead, cinnabar, mercury, and earth) symbolize the Five Phases' refined essences within the human body. True lead (referring to Primordial Qi) appears outwardly like ordinary black lead but contains golden radiance within. This resembles a person wearing coarse cloth yet harboring jade within their heart, or appearing mad while possessing extraordinary wisdom. This constitutes the fundamental distinction between true lead (Primordial Qi) and ordinary lead. Understanding how "white" (Yang) is concealed within "black" (Yin) naturally allows one to perceive this marvelous energy.

The key to Golden Elixir (Jindan) cultivation lies in discovering "metal within water" (the primordial essence contained in kidney water). As the Scripture of Entering the Medicine Mirror states: "Only the lead from water's homeland," and the Awakening to Reality Treatise declares: "White within black becomes the elixir's mother" - both refer to this principle.

Metal (lung metal) serves as mother to water (kidney water), with the mother hidden within the child; water acts as metal's child, yet the child envelops the mother. This interdependent relationship mirrors the existence of the True Person (original spirit), which seems both present and absent, like something appearing and disappearing in deep waters. During practice, metal and water energies first unite, then return to their respective positions: metal energy ascends while water energy descends, forming the celestial cycle.

Golden essence inherently generates water as its source. The true metal of the Qian hexagram hides within the water of Kun hexagram, like a mother concealed within her fetus; while the true water of Kun hexagram is contained within the metal framework of Qian hexagram, like a child embracing its mother. This metal-water mutual generation represents the intercourse of Yin and Yang energies. When complete fusion occurs, the True Person (original spirit) manifests. Residing in the Central Palace (Yellow Court), its existence transcends being and non-being, remaining profoundly mysterious. During cultivation, metal and water energies first converge at the center before returning to their positions: metal energy ascends to the heart in the south, water energy descends to the kidneys in the north, completing the cultivation cycle.

This passage elucidates the crucial process of "gathering medicinal ingredients and returning them to the furnace" in Daoist Neidan (internal alchemy) practice. The primordial essence (Jing) of metal within the northern Kan trigram (the water trigram of the Bagua), originally pure and untainted, radiates brilliance when tempered by the true fire of the southern Li trigram (fire trigram). This resembles extracting crimson essence from white raw material. This innate true seed is neither substantial nor void, possessing an exceedingly subtle nature that requires the nurturing protection of the "Kun mother" (the womb of all creation) at the central yellow region (the core of the Dantian) to remain steadfastly anchored within the divine chamber (Dantian) without wavering.

The scripture depicts the symbolic furnace and cauldron of alchemy: this divine chamber measures merely one square inch, with its round shape representing heaven and square base symbolizing earth, housing the "true person" (original spirit) at its center. This aperture, known as the "primal pass," existed before the formation of heaven and earth, containing the universe's most primordial energy. Situated at the body's central axis, it connects all parts of the human form like the legendary Penglai immortal isle. Practitioners must firmly guard this aperture to prevent essence-energy leakage while resisting external disturbances. Though this spiritual aperture remains inherently unobstructed, adepts must maintain constant vigilance against potential dangers.

During cultivation, one should maintain mental serenity, avoiding excessive contemplation or anxiety. When spirit (Shen) and Qi fully permeate the Dantian, this state becomes naturally sustained. The essential principle lies in harmonizing movement and stillness, allowing the cultivated state to integrate seamlessly with daily life. While ostensibly describing the furnace-cauldron imagery, this passage actually contains the oral instructions (huohou) regarding the rhythmic timing of alchemical practice.

This scripture primarily elucidates the essential principles of Neidan (internal alchemy) practice and methods for discerning heterodox paths.

Regarding cultivation: Every individual inherently possesses primordial ancestral Qi (innate vital energy), which originally permeates the entire body, though ordinary people struggle to sustain it long-term. Practitioners must fill this "divine chamber" (Dantian, energy center) within the body with Shen-Qi (spirit and vital energy), maintaining unwavering focus and vigilance at all times. The slightest lapse can lead to the dissipation of this vital energy. The key lies in harmonizing movement and stillness naturally, synchronizing completely with the breathing rhythm of the body's true Qi—moving when it moves, resting when it rests, and pausing when it pauses. This state must be sustained effortlessly, neither forced nor neglected, in an unbroken continuum, ensuring the "fire timing" (the rhythm of practice) reaches perfection. This is what is known as the work of refining the "furnace and cauldron" (the body) and nurturing primordial energy.

Regarding distinguishing the orthodox from the heterodox: The scripture enumerates various fallacies of deviant practices. For instance, some methods involve forced internal visualization of organs, indulging in wild imaginings; others engage in elaborate rituals, exhausting the body through ceaseless activity day and night; some worship spirits and deities, becoming lost in illusions; while others deviate from the true path of the Yellow Emperor and Laozi, straying from fundamental cultivation principles. Though these methods may appear numerous, they are ultimately heterodox paths that contradict the Dao. Those with genuine understanding can discern them clearly at a glance, recognizing the correct path of cultivation.

The text particularly emphasizes that to comprehend the orthodox path, one must first recognize the errors of heterodox methods. Though deviant practices may seem varied, they all fundamentally violate natural principles, relying on forced and delusional cultivation methods.

This passage critiques several common deviations from the authentic Daoist path:

The first is the practice of internal visualization of the five organs and forced meditation (cunxiang), which represents a misguided attachment to mental constructs. The second involves ritual footwork (bugang tadou) and talismanic calculations based on astrological timing (fuzhou), representing rigid adherence to ceremonial techniques. The third is the sexual cultivation method of "gathering yin to supplement yang," which disrupts primordial Qi (yuanqi). The fourth consists of breathing techniques that involve swallowing external Qi or forced exhalation/inhalation, representing the dangerous absorption of pathogenic energy. The fifth is the extreme practice of prolonged sitting meditation without sleep, which depletes vital essence (Jing) and energy (Qi).

All these methods represent physical cultivation deviations that only exhaust the body, confuse the spirit (Shen), and disrupt the harmonious flow of Qi and blood, leaving practitioners without a moment of true peace.

Another deviation involves morning and evening sacrifices to spirits, seeking supernatural manifestations. Practitioners may initially feel self-satisfied, believing they're prolonging life, unaware they're becoming possessed by negative entities. Ultimately this leads either to calamity or strange illnesses—those seeking longevity ironically meet premature deaths, their decaying corpses becoming objects of ridicule. This outward-seeking deviation produces particularly evident negative consequences.

The author emphasizes that the true Golden Elixir (Jindan) path lies in cultivating one's innate nature, far surpassing these misguided methods. All such practices violate the fundamental teachings of the Yellow Emperor and Laozi. Discerning practitioners should comprehend these truths and recognize the authentic path.

This passage from Can Tong Qi Chan You elucidates the core principles of Daoist cultivation. It explains that the Yinfu Jing and Daode Jing directly reveal the supreme method of dual cultivation of nature and life (xingming shuangxiu), which aligns perfectly with the original intent of the Yijing as transmitted by the three sages—Fuxi, King Wen, and Confucius. Unfortunately, most people fail to grasp this truth, often straying into misguided practices that lead to countless erroneous paths of cultivation.

The author identifies five or six common deviations: some focus solely on internal bodily practices, while others seek enlightenment exclusively through external means. These are all partial understandings, when in reality the Dao of cultivation is vast and intricate. True practice either follows the method of "returning to the root of life" (fuming guigen) as taught by the Yellow Emperor and Laozi, or it delves into the mysteries of the "Nine Palaces and Cavern Chamber" (jiugong dongfang), referring to key areas of the body in Daoist practice. Those who take the wrong path are like someone walking backward in an attempt to move forward—wasting their energy in vain.

A truly wise practitioner should maintain firm resolve, seek out enlightened teachers, and investigate the source of nature and life. If one can grasp the truth through a single illuminating phrase, they will realize that this has always been a straightforward path accessible to all. With sustained practice, one can transcend delusions and attain extraordinary states.

The latter part of the text specifically explains the essential method of "subduing and ingesting" (fushi, a Neidan term referring to the harmonization of Yin and Yang and the fusion of nature and life). Earlier chapters discuss the principles of Yin-Yang and the essence of nature and life, while fushi involves the profound application of their interaction—the crucial process in refining the Golden Elixir (jindan). "Subduing" (fu) signifies the mutual restraint of two substances, while "ingesting" (shi) denotes their unification. Here, lead and mercury (waidan terminology) serve as metaphors for the true seeds of nature and life, and the cauldron and furnace (alchemical tools) symbolize the transformation of body and mind. Through tangible symbols, the intangible Dao is revealed—this is the true meaning of fushi, far removed from the superficial practices of those who merely burn herbs and play with fire.

The final section on the "union of the two crescents" (liangxian heti) uses lunar phases as an analogy for cultivation: the first quarter (Dui trigram) on the eighth day and the last quarter (Gen trigram) on the twenty-third day each span eight days, representing the balance of Yin and Yang. Just as sixteen taels make up one jin (Chinese pound), with each crescent accounting for eight taels, the harmonious interplay of these two halves completes the Great Dao of the Golden Elixir. This is the orthodox path illuminated by the Yijing.

This passage discusses the separation and union of the Metal and Wood energies (Jin-Mu er qi) during alchemical practice, revealing the true substances of internal alchemy (Neidan). The so-called "Fire Records" (Huoji) are not fabricated notions but are explained through the principles of the Yijing (Book of Changes). Here, the "crescent moon" (Yanyue) metaphorically represents the alchemical furnace and cauldron, the "White Tiger" (Baihu) symbolizes the crucial element of refinement, while "mercury" (Gong) flows like liquid pearls, with the "Azure Dragon" (Qinglong) acting in coordination—their east-west union resembles the interdependence of hun and po (ethereal and corporeal souls).

The author clarifies that while earlier sections on nurturing inner nature (xing) emphasized the great Dao (Da Dao) of emptiness and spontaneity, this section specifically details the practical operations of alchemy, focusing on the two substances of Metal and Water. Technical terms like furnace-cauldron, lead-mercury (Qian-Gong), dragon-tiger (Long-Hu), and the lunar phases (upper and lower crescents) all serve as metaphors for these substances. The ancient alchemical legend of "600 chapters of Fire Records" never actually existed—Wei Boyang invoked this concept metaphorically when composing the Cantong Qi (The Seal of the Unity of the Three). The true principles of the "Fire Records" are embedded in the Yijing, using the sun and moon to symbolize yin-yang transformations.

Here, Qian (Heaven) and Kun (Earth) represent the furnace-cauldron, Kan (Water) and Li (Fire) symbolize the medicinal substances, while the remaining sixty hexagrams with their 360 lines depict the variations of firing times (huohou). Each day corresponds to two hexagrams, and one lunar month perfectly aligns with the 360-degree celestial cycle. Expanding one month to a full year yields the so-called "600 chapters of Fire Records," which fundamentally still express the principles of yin-yang alternation.

The Kan hexagram embodies the true lunar essence (Taiyin zhenshui), yet it must harmonize with solar energy. During the moonless transition between lunar phases, when yin culminates and transforms into yang, the moon generates nascent yang energy. On the third evening of the lunar month, the western sky reveals the stirring of initial yang through the Zhen hexagram—the crescent moon's shape resembles metal emerging from water, termed "the Tiger is born from water" (Hu xiang shui zhong sheng). The latent Metal energy (Jin qi) concealed within the furnace requires tempering before manifesting, forming the Dui hexagram state akin to the upper crescent moon. Conversely, the Li hexagram symbolizes the true solar fire (Taiyang zhenhuo), which must integrate with lunar energy. At full moon, when yang culminates and transforms into yin, the sun contains latent yin energy. On the sixteenth day at dawn...

This passage elucidates the profound principle of "combining the two crescents to form the elixir" in Daoist Neidan (internal alchemy) practice. The "two crescents" refer to the waxing moon (represented by the Dui trigram) and waning moon (represented by the Gen trigram) in the lunar cycle, symbolizing the waxing and waning transformations of Yin and Yang energies.

The waxing moon (Dui trigram) corresponds to the number eight, when Yin energy begins to emerge—like a young maiden (Dui symbolizes the maiden trigram)—with the trigram secretly containing the golden soul (Yin energy). The waning moon (Gen trigram) also corresponds to the number eight, when Yang energy begins to arise—like a young boy (Gen symbolizes the youth trigram)—with the trigram secretly containing the aqueous spirit (Yang energy). When these two energies intermingle, it resembles combining half a pound of gold with half a pound of water, ultimately forming the complete measure of "one pound," symbolizing the perfected state of Yin-Yang equilibrium.

Practitioners must seize these two critical moments: during the waxing moon to gather the energy of the Azure Dragon of the East (Wood-phase Yang energy), and during the waning moon to guide the energy of the White Tiger of the West (Metal-phase Yin energy). When dragon and tiger meet, when metal and wood merge, the celestial soul (Yang spirit) and earthly essence (Yin jing) will naturally unite, much like the union of young maiden and youth. This harmonious interaction of Yin and Yang ultimately crystallizes into the Golden Elixir within the practitioner's "central yellow earthen cauldron" (Dantian).

Of particular importance is that although the practice involves separately gathering Yin and Yang energies during the two crescent phases, the perfected Golden Elixir ultimately transcends all distinctions between them. Just as the moon transforms from crescent to full, it ultimately manifests as a complete circle. This reveals the fundamental Daoist cultivation principle of "Yin and Yang sharing common roots, opposing yet completing each other."

This scripture primarily elucidates the significance and cultivation principles of "golden nature" (primordial Qi) in Daoist Neidan (internal alchemy) practice.

Regarding lunar phases, the text explains that when the moon's waxing and waning crescents unite (referring to the half-moon phases on the 8th and 23rd lunar days), the lead and mercury (Neidan terminology representing yin and yang energies) each measure exactly half a jin (eight taels), combining to form the perfect one-jin measure of the Golden Elixir. This process originates from the Gen (mountain) and Dui (lake) trigrams of the Bagua (Eight Trigrams), which emerge from Kan (water) and Li (fire) - the latter symbolizing the sun and moon. When yin and yang achieve equilibrium, practitioners can avoid deviations in cultivation.

The chapter on "gold returning to its nature" emphasizes that primordial golden nature (pure yang energy) constitutes the fundamental basis of cultivation. Just as worldly gold becomes more radiant when tempered in fierce flames, this primordial golden nature - originating from cosmic origins - remains indestructible through countless kalpas. During cosmogenesis, yang energy from the Qian (heaven) trigram transformed into the Li (fire) trigram, while yin energy from the Kun (earth) trigram became the Kan (water) trigram. The true gold within Kan (water's metal) tempered by Li's true fire achieves indissoluble cohesion, mirroring the eternal movement of sun and moon.

The text clarifies that while refined worldly gold maintains its weight unchanged, this primordial golden nature transcends all transformation. The essence of cultivation lies in returning the postnatal yin-yang energies (the two crescents) to their prenatal state of pure golden yang nature - the foundational principle of the Golden Elixir's Great Dao.

Within the great crucible of Heaven and Earth, the myriad things undergo endless transformations, yet the total quantity of gold-nature (jinxing) remains constant—neither increasing nor decreasing. Just as the sun and moon have circled for countless millennia, though passing through infinite cycles of waxing and waning, their fundamental essence remains eternally unchanging. This is precisely because the nature of gold never perishes.

The essence of gold-nature is unitary, though the sun and moon each carry different aspects: the sun primarily radiates light outward, while the moon chiefly gathers essence inward. In truth, the sun and moon are originally one body, and essence (jing) and light are not separate things. The golden essence within the moon may appear to dwell within the lunar body, yet it is actually nurtured by the sun. When people observe the first sliver of moonlight appearing in the west (the Geng direction) on the third night of the lunar month, they mistake it for the moon's own radiance, unaware that this glimmer originates from the sun—during the conjunction of sun and moon at month's end and beginning, the sun's light reflects back upon the lunar body like conception.

When the moon is completely dark (on the last day of the lunar month), the sun and moon unite like mating partners: the sun above, the moon below, with the sun's essence absorbed by the moon while the moonlight is enveloped by the sun. At this moment, Heaven and Earth plunge into darkness, symbolizing gold-nature returning to its source (Kun-earth). Here, the sun's light lies hidden in the Void and Danger constellations (Xu and Wei stars of the northern Black Tortoise in Daoist cosmology), while a single drop of golden essence sinks into the abyss of the North Pole. In cosmic terms, this is called "the sun and moon joining like jade disks, the celestial pivot halting its turn" (the stillness of heavenly phenomena); in human cultivation, it corresponds to "the spirit (shen) returning to the Qi-cavity, the great medicine (dayao) entering the furnace" (Neidan terminology denoting the coalescence of essence, Qi, and spirit).

Soon, when yin reaches its extreme, yang is born anew, and faint light reappears in the west (the Geng direction belonging to metal). In Heaven and Earth, this manifests as the birth of the new moon; in human cultivation, it symbolizes the "great medicine" (the refined essence gained through practice) ascending from the lower Dantian (Kun-furnace) to the upper Dantian (Qian-cauldron). Only now does the true gold within the Kan trigram (symbolizing the moon) fully return to its origin, reverting to its original Qian-yang nature.

(Note: This scripture uses the sun-moon cycle as a metaphor for Neidan practice. Here, "gold" refers both to physical gold and to the indestructible primordial Qi within the human body; "the golden essence within Kan" denotes the primordial essence (yuanjing) contained in kidney-water; "Qian-father and Kun-mother" represent the source of yin and yang energies.)

This passage elucidates the pivotal role of "golden nature" (referring to the innate essence, a pure and indestructible quality like gold) in both the cosmos and the human body. Golden nature serves as both the origin and ultimate destination of all creation, mirroring the endless cycle of Yin-Yang in the Taiji diagram.

The cosmic creative process follows the patterns of the Hetu (an ancient cosmological diagram): Water (one of the Five Phases) emerges first, then generates Wood; Wood generates Fire; Fire generates Earth; and finally Earth generates Metal. Though Metal appears last in sequence, it contains the complete energy of all Five Phases. Tracing backward, Earth originates from Fire, Fire from Wood, Wood from Water, while Water itself ultimately stems from Metal—thus making Metal the source of the entire Five Phases cycle. This forms a seamless, self-perpetuating circle.

In the human body, golden nature manifests as our innate primordial essence (ancestral nature). Before our parents conceived us, this essence existed in perfect purity like the void; when seminal essence (Jing) and blood unite to form the physical body, this true nature descends into the corporeal form to animate life. Though the physical body will eventually perish, this golden nature remains indestructible, enduring through all kalpas (cosmic cycles).

When Fu Xi drew the Eight Trigrams (Bagua), his initial stroke created the Qian hexagram (representing Heaven). Confucius explained Qian as "the origin of all things" and described it as "pure and refined"—precisely the principle practitioners must comprehend to penetrate life's essence. Shakyamuni Buddha realized this truth to attain his golden-hued dharma body (a Buddha's majestic form), revered as the Golden Immortal; the Celestial Worthy of Primordial Beginning (Yuanshi Tianzun, Daoism's supreme deity) likewise crystallized the Golden Elixir (Jindan, the highest achievement in Neidan practice). The fundamental teachings of Confucianism, Buddhism, and Daoism all root in this golden nature—any deviation constitutes heterodoxy.

This passage reveals how the term "golden nature" encapsulates the core doctrine of the Three Teachings' sages, disclosing celestial secrets. Thus, the Scripture of the Kinship of the Three (Cantongqi) proves essential reading for all seekers, worthy of perpetual study. Herein lies the essential meaning of Chapter Eleven: "The Creative Transformation of True Earth."

This passage explains the core principles of Neidan (internal alchemy) practice in Daoism, focusing on how to form the Golden Elixir through harmonizing the Five Phases' energies within the body. The essence lies in the dynamic of "water and fire mutually aiding each other" and the mediating role of "central true earth."

The numerical values of the Water hour (midnight) and Fire hour (noon) sum to three, while Wutu (yang earth) and Jitu (yin earth) combine to make five. When these three fives (representing the harmony of water, fire, and earth) operate in coordination, they regulate the movement of the body's eight essential substances (the "eight minerals"). Each breath contains the creative energy of all things, much like conjugal union generates new life.

In the Five Phases relationships: Yellow Earth (spleen earth) generates Metal (lung metal), while flowing mercury (representing the Shen/spirit) is produced by Water, which in turn is restrained by Earth (earth overcomes water). The Vermilion Bird (heart fire) represents fire's essence and requires balance—excessive water extinguishes fire, so both must return to nurturing earth for harmonization. When water, fire, and earth energies unite, they return to primordial nature.

Practitioners consuming "Jusheng" (a longevity herb) may extend their lifespan, but the true marvel comes when the Golden Elixir enters the abdomen. Since gold's nature never decays—being the essence of all things—ingesting it grants immortality. The spleen earth (central Yellow Court) governs the four seasons' cycles, maintaining the body's systemic order.

Once the Golden Elixir enters the body, its medicinal power spreads through the organs like wind and rain, with vaporous energy reaching the limbs. This transforms the practitioner: complexion glows, white hair darkens, lost teeth regrow, elders regain youth, and old women recover maidenhood. Such complete metamorphosis beyond life and death defines a "Zhenren" (Perfected Being).

The text particularly emphasizes the crucial role of Wuji earth (primordial true intention) in alchemical practice. During cultivation, heart fire (Jitu in the Li trigram) and kidney water (Wutu in the Kan trigram) must be mediated by the central true intention (Yellow Court spleen earth). Though water and fire naturally oppose each other, only the central earth's De (virtue/power) can reconcile them into productive interaction. Water's one, fire's two, plus central earth's five complete the Bagua (Eight Trigrams) orientation, forming the body's holistic energy system—this is the profound meaning of "the harmony of three fives."

This passage elucidates the core principles of Daoist Neidan (internal alchemy) cultivation. Initially, it mentions the "Eight Minerals" (ba shi, eight alchemical minerals) and "Five Metals" (wu jin, five metallic substances) representing Waidan (external alchemy), but these are actually metaphors for internal cultivation. The true Golden Elixir (jindan) practice doesn't rely on these external materials, but rather on harmonizing the Yin and Yang energies within the body.

The crux of cultivation lies in "true respiration" (zhenxi)—not ordinary breathing through nose and mouth, but the intrinsic flow of vital energy—where fire and water energies naturally merge in the Central Palace (the Dantian region) like a harmonious marital union. This internal respiratory cycle continuously circulates, forming the "true embryo" (zhentai, the nascent form of the internal elixir). Classics like the Nanhua Jing and Huangting Jing all describe this profound operation of life energy.

Using directional symbolism: the north represents water, the south represents fire. But more profoundly, it refers to the water nature within the Li trigram (symbolizing fire) and the fire nature within the Kan trigram (symbolizing water), illustrating how Yin and Yang mutually contain each other. Just as the Vermilion Bird (zhuque, essence of fire) requires tempering, when water and fire contend, the mediating earth element (the true intention of the Central Palace) is needed to restore equilibrium.

The passage ultimately emphasizes the pivotal role of "true earth" (zhen tu, the genuine intention of the Central Palace), which enables the Five Phases (wuxing) energies—metal, wood, water, fire, and earth—to return to their unified origin. This "true earth" is humanity's innate primordial spirit (yuanshen), the original nature derived from the Qian trigram (pure Yang). When Qian's Yang descends into Kun's Yin to form the Kan trigram, the metallic nature (primordial qi) contained within becomes the fundamental basis for cultivating the Golden Elixir.

This passage explains the core principles of mutual generation and restraint between Yin-Yang and the Five Phases in Daoist Neidan (internal alchemy) practice. When a single drop of Yang energy from the Qian trigram (representing Heaven and Yang) enters the Kan trigram (representing Water), its center transforms into Yin energy, forming the Li trigram (representing Fire), which actually originates from the Kun trigram (representing Earth and Yin).

The Wood-phase liquid (referring to human Jing-essence) within the Li trigram is called the "Sun's Flowing Pearl." Generated from the maternal Kun trigram, it's therefore called "Water's child." This describes the generative relationships among the Metal, Wood, and Earth phases: the Metal-phase essence in Kan trigram is the "Sun's True Fire," while the Wood-phase liquid in Li trigram is the "Moon's True Water."

The Yin water in Li trigram tends to overflow and restrain the Yang fire in Kan trigram. At this point, the fire in Kan trigram generates central True Earth (referring to spleen Earth Qi) to control it, hence the saying "Water takes Earth as its demon" (Earth can suppress water). The central True Earth both restrains the True Water in Li trigram, while the fire in Kan trigram generates the central True Earth—thus when water and fire restrain each other, the central True Earth mediates their balance, preventing either from becoming excessive.

The Vermilion Bird (representing fire), as fire's essence, must maintain equilibrium. Excessive fire tends to flare upward and requires True Water to harmonize it; overwhelming water needs True Earth to contain it. When fire nature is fully transformed, it ceases to flare; when water nature is fully transformed, it ceases to overflow—both ultimately returning to True Earth. This explains the restraining relationships among Metal, Wood, and Earth.

Whether considering generation or restraint, everything begins from the central True Earth. The key to alchemy lies in this "True Intention" (the practitioner's focused awareness), which governs the cycle of life and death. Following this principle leads to endless regeneration, while reversing it enables transcendence of rebirth. Cultivation both begins and culminates here.

The True Water of Li trigram, True Fire of Kan trigram, and central True Earth appear as three distinct natures before unification, but their fundamental unity becomes apparent after merging. Like the primordial Taiji (Supreme Ultimate) containing the Three Powers (Heaven, Earth, and Humanity)—an undivided cosmic heart—they were originally one. Only after the primal chaos separated did water and fire divide, with central Earth forming the third element, creating the distinction among these three aspects.

This passage elucidates the mystery of "Three Natures Merging into One" in Daoist Neidan (internal alchemy) practice. Initially, the two Qi (vital energies) of Yin and Yang (the dual lunar energies) remain separate. Through the mediation of Wu-Earth and Ji-Earth (two central earth energies representing the center), they ultimately reunite in the Central Palace (Dantian, the energy center). Master Zhang Ziyang's saying "pursuing the two Qi along the Yellow Path, uniting the three natures in the Primordial Palace" describes precisely this process. The text first uses the metaphor of husband and wife to illustrate the matching of Yin and Yang, then employs father and son to represent the origin of these two energies, finally using ancestors to symbolize the state of their trinity.

Kan (Water) and Li (Fire) symbolize the marital couple, while Qian (Heaven) and Kun (Earth) represent the parental pair—these are the symbolic manifestations of the Two Forms and Four Phases. The Central Ancestral Earth (the Central Palace) becomes the locus for returning to the Taiji (Supreme Ultimate) origin, embodying the profound mystery of returning to the root and restoring life's mandate.

The subsequent section describes the miraculous effects of ingesting the Golden Elixir. If mundane herbs like sesame seeds can prolong life, how much more so the immortal Golden Elixir? When practitioners ingest this primordial Qi, they naturally achieve longevity and luminous vision. The Wu and Ji earth energies circulate through the four seasons (represented by the Chen, Wei, Xu, and Chou directions)—establishing the Central Palace foundation during alchemical refinement, and demarcating the four boundaries during elixir ingestion.

After the Golden Elixir (golden cinnabar) enters the body, it disperses like wind, rain, and mist throughout the entire form, reaching all four limbs. It makes one's countenance radiant, turns white hair black, regrows lost teeth, restores youth to the aged, transforms elderly women into maidens, alters physical appearance, and liberates from the cycle of life and death—this is what constitutes a Zhenren (Perfected Being). The phrase "entering the five interiors" refers to the elixir settling in the "inch-square" heart field, not the mundane concept of material ingestion. After the Golden Elixir enters the mouth, it produces various miraculous transformations—all verifiable through natural manifestations.

This passage describes the wondrous physical transformations that occur when one reaches advanced stages of cultivation. At a certain level of practice, all eighty-four thousand pores of the body open like rising mist and clouds, the limbs naturally extend, and the entire being becomes renewed as if cleansed by wind and rain. The complexion turns radiant with a healthy glow, white hair darkens, lost teeth regrow, elderly men regain the physique of their prime, and aged women recover their youthful appearance. Such a state transcends the limitations of cosmic cycles and natural laws—even as oceans turn to mulberry fields, these practitioners remain carefree and unbound. Only those who achieve this may truly be called "Perfected Persons" (Zhenren).

The text then explains the alchemical principle of "like attracting like." Just as lead white reverts to lead when heated, or ice and snow melt into water when meeting warmth, elixir refinement must follow this natural correspondence. Cinnabar serves as the primary ingredient combined with mercury precisely because they share intrinsic affinity—like planting rice with rice seeds or hatching chickens from chicken eggs. Defying this principle yields no results: fish eyes cannot become pearls, nor can wormwood grow into catalpa trees.

Many Daoist practitioners in the world, though naturally gifted, labor in vain because they misunderstand this truth. They haphazardly mix incompatible minerals like chalcanthite, mica, alum, magnetite, and sulfur, or attempt to assist their elixirs with five different metal ores, inevitably failing because these substances fundamentally cannot harmonize. Countless seekers waste their youth to hoary age in such futile efforts, harboring doubts yet never realizing they've taken the wrong path.

Particularly crucial is understanding water-fire interaction. Ordinary people recognize Kan (☵) as representing water, yet fail to perceive its central solid line—derived from Qian (☰)—as the true solar fire. They know Li (☲) symbolizes fire, but miss that its broken central line—sourced from Kun (☷)—embodies lunar water. Thus authentic elixir cultivation requires the true fire within Kan to unite with the true water within Li—this constitutes the essence of "like attracting like." Those who ignorantly pursue external alchemy (Waidan) without grasping this principle will never obtain the genuine Golden Elixir (Jindan).

This scripture elucidates the core principle of Daoist Neidan (internal alchemy) cultivation—the harmony of Yin-Yang and the law of like attracting like. Using the metaphor of "gold within water" (referring to the body's innate primordial Qi) and "cinnabar within Li" (symbolizing the heart-mind), it explains the essence of dual cultivation of nature and life (xingming shuangxiu).

First, it describes nature's fundamental patterns: water's nature flows downward while fire's nature flames upward—these are the intrinsic qualities of all creation. Just as lead white (a cosmetic powder) derives from black lead through firing and reverts to lead when heated, or as ice and snow (condensed from cold water) melt back into water when warmed, all things inevitably return to their origin.

The crux of Golden Elixir (Jindan) cultivation lies in extracting "gold within water"—the innate primordial Qi (life-root) from the Mingmen (life gate). This Qi originally stems from the pre-heaven Qian trigram (pure Yang), but in the post-heaven transformation into Li trigram (fire), its concealed true Yin (represented as cinnabar) requires balancing by the true Yang (represented as mercury) from kidney-water in the northern direction. Here, cinnabar symbolizes the heart-mind (Shen) while mercury represents original essence (Jing)—two aspects that emerged from the same source and must ultimately reunite.

Master Zhang Ziyang (a renowned Song dynasty Neidan practitioner) taught: Yin and Yang must share the same category to interact, just as a sixteen-year-old maiden (Yin) naturally pairs with a sixteen-year-old youth (Yang). The cultivation's pivotal point lies in returning the post-heaven water-fire (Kan-Li) relationship to its pre-heaven Qian-Kun state.

Subsequent passages illustrate the importance of "like attracting like" through analogies: grain seeds produce crops, chicken eggs hatch chicks—things of different categories cannot transform each other. Fish eyes cannot become pearls, wormwood won't grow into catalpa trees, sparrows don't give birth to phoenixes, nor can foxes nurse colts. Just as water doesn't spontaneously heat itself nor fire moisten itself, cultivation must follow nature's law of Yin-Yang correspondence.

The secret of "Fu Shi" (ingesting the Golden Elixir) resides in mastering the mutual transformation between cinnabar (heart-mind) and mercury (original essence)—two substances sharing the same origin but bearing different names.

The key to refining the Golden Elixir (Jindan, a Daoist term referring to alchemically perfected medicine) lies in the harmonious interaction of corresponding substances. Just as cinnabar (Zhusha) is refined using gold, or when elixirs are ingested to nourish the five viscera (Wunei), these processes follow the principle of "like begets like." Without this correspondence between substances, the alchemical transformation leading to immortality cannot be achieved.

All things in the world adhere to the principle of "birds of a feather flock together." Just as crops require grain seeds and chickens hatch from eggs, corresponding substances naturally assist one another and easily fuse into transformation. Forcibly combining incompatible elements is like expecting fish eyes to become pearls, mugwort to grow into mighty trees, sparrows to give birth to phoenixes, or foxes to bear colts—their intrinsic natures are fundamentally different. Water's nature is to moisten and descend, while fire's nature is to blaze upward. Water and fire each follow their own nature, just as the Kan trigram (representing water) and Li trigram (representing fire) belong to their respective categories. This is precisely why cinnabar and mercury (essential ingredients in Daoist alchemy) can mutually transform to form the Golden Elixir.

Many scholars today, despite their remarkable intelligence, waste their resources because they lack proper guidance from enlightened masters. Rigidly adhering to written records, they mix incompatible minerals like Qiangshidan (a type of mineral), mica, alumite, magnetite, and sulfur with clay and mercury, attempting to refine elixirs using bronze-smelting techniques. How can such disparate substances possibly succeed? After countless failed attempts, their supposed wisdom only reveals folly. Some persist from youth until white-haired old age, occasionally doubting but still stubbornly following misguided paths. Like viewing the sky through a bamboo tube—how can those with such narrow vision grasp the true method of cultivation? Those who rely on mere chance will never encounter the true Dao (the Way). Only sages comprehend its profound meaning.

This passage specifically refutes the errors of external alchemy (Waidan, the practice of refining elixirs through mineral smelting), pointing out that all tangible substances are not the true materials for cultivating the Golden Elixir. To refine the authentic Reverted Elixir (Huandan, a Neidan term referring to the internal elixir formed through cultivating essence, qi, and spirit), one must employ the formless primordial substances of nature and life (Xingming, where Xing represents the original spirit and Ming represents primordial qi). These substances are metaphorically called lead and mercury (Qianhong, representing the yin and yang qi within the body), entirely distinct from ordinary cinnabar and mercury. True alchemy requires establishing an internal "furnace and cauldron" (a metaphor for the body's cultivation center) where these medicinal substances are refined...

This scripture elucidates the true essence and common misconceptions of cultivating the Golden Elixir (Jindan) path. It clarifies that authentic alchemy employs the "Primordial True Fire" (referring to the innate Qi within the human body), fundamentally distinct from the external alchemy (Waidan) practices of burning herbs or smelting ores. The refinement of the Golden Elixir requires precise mastery of "fire phases" (the rhythm and intensity of practice), progressing through three stages—refining, nurturing, and transforming—until finally coalescing into the "perfectly rounded pearl" (symbolizing the internal elixir or Neidan), the sacred embryo.

The author sternly criticizes those who, without seeking guidance from enlightened masters, presumptuously misinterpret alchemical classics through their own cleverness. Such practitioners mistakenly take common minerals as "lead and mercury" (alchemical terms representing Yin-Yang energies), conflating external elixir preparation with internal cultivation. Not only do they waste resources, but they may also forfeit their lives. Their narrow, superficial understandings, like viewing the sky through a bamboo tube, have been compiled into misleading texts that obstruct the genuine path of practice.

The text particularly emphasizes that the authentic Golden Elixir path is extraordinarily rare and precious, requiring direct transmission from master to disciple. The previous three chapters have fully revealed the essential principles: the first discusses the two energies of Yin and Yang (the dual celestial breaths), the second addresses the innate golden nature (humanity's original true essence), and the third explains the convergence of the Three Treasures (Jing, Qi, and Shen). Yet ordinary people often become deluded by heretical methods of external alchemy, hence this chapter reiterates the need to dispel such confusion.

The passage concludes by quoting Lü Dongbin's cautionary verse: The true Reverted Elixir (Huandan) is formless vital essence; those who ingest metals and minerals are profoundly foolish. This perfectly reflects the profound intent of the immortal Wei Boyang (Xianweng) in rectifying these errors.

In the section "Transmission from the Three Sages," it explains that among the three sages who transmitted the Zhouyi: Fuxi originated the Eight Trigrams (Bagua), modeling heaven and earth; King Wen of Zhou expanded them into sixty-four hexagrams and composed the line statements; Confucius authored the Ten Wings to elucidate the principles. Though their individual contributions varied in depth, these three sages successively arose to collectively perfect the system of the Yi Dao.

This passage traces the lineage and significance of the Zhouyi (Book of Changes). Three sages—Fuxi, King Wen of Zhou, and Confucius—successively perfected its system, unveiling the profound mysteries of the cosmic Dao (the Way).

In primordial times when chaos still prevailed, the Dao (the Way) existed without form or image. It was Fuxi who first created the Bagua (Eight Trigrams), ancient divinatory symbols, by observing celestial and terrestrial patterns. Heaven then manifested the Hetu and Luoshu (legendary mystical diagrams) as confirmation, revealing that all phenomena originate from Taiji (the Supreme Ultimate). Taiji encompasses the two polarities of Yin-Yang, which further generate the Four Symbols and Eight Trigrams, forming a complete cosmological framework.

King Wen of Zhou expanded this foundation by deriving the hexagram and line statements, while Confucius supplemented them with the Ten Wings (ten commentaries interpreting the Zhouyi). Though their contributions came in sequence, all three sages achieved equally magnificent merit. Through meticulous deduction, they transformed the formless heavenly principles into a tangible system of symbols, establishing an enduring canonical model for posterity.

The author notes that while texts like the Fire Chronicles and six hundred other alchemical classics (Neidan and Waidan scriptures) employ solemn language, people seldom contemplate their origins deeply. In truth, the principles of Yin-Yang's manifestation and concealment share a unified source. This explanation is offered specifically for those with spiritual aptitude—how dare one compose such works lightly? To remain silent might sever the Daoist transmission, yet reckless disclosure of celestial secrets risks offense. Thus, only an outline can be cautiously presented, much like cultivating trees requires following natural laws, precluding exhaustive elaboration.

The text emphasizes the Zhouyi as essential for Daoist cultivation. Through the symbolic system, the three sages translated the formless Dao into a knowable, transmissible body of knowledge.

This passage explores the profound mysteries of the Eight Trigrams (Bagua) from the Book of Changes (Yijing) — Qian (Heaven), Kun (Earth), Zhen (Thunder), Xun (Wind), Kan (Water), Li (Fire), Gen (Mountain), and Dui (Lake). The Primordial (Xiantian) arrangement established by Fu Xi positions Qian (pure Yang) in the south, Kun (pure Yin) in the north, Li (Fire) in the east, Kan (Water) in the west, Dui in the southeast, Gen in the northwest, Xun in the southwest, and Zhen in the northeast. In this configuration, the trigrams of pure Yin-Yang occupy the cardinal directions, while those blending Yin and Yang reside in the corners, symbolizing the cosmic order of Heaven-Earth positioning and the movement of sun and moon.

Later, when King Wen of Zhou was imprisoned, he reorganized the trigrams into the Acquired (Houtian) arrangement: Li (Fire) shifted from the east to the south, replacing Qian to represent universal illumination; Kan (Water) moved from the west to the north, replacing Kun to signify nurturing all things; Zhen (Wood/Thunder) advanced from the northeast to the east, taking Li's former position as wood generates fire; Dui (Metal/Lake) withdrew from the southeast to the west, replacing Kan since metal produces water. The fatherly Qian was placed in the northwest, the motherly Kun in the southwest, the youthful Gen in the northeast, and the elder Xun in the southeast. This new arrangement positioned interactive, dynamic trigrams in the cardinal directions while placing the less interactive, aged ones in the corners, emphasizing the principle of "transformative exchange."

The cyclical movement of the trigrams begins with Zhen (Thunder) and concludes with Gen (Mountain), endlessly generating and transforming all existence. This embodies the Book of Changes' core philosophy of "perpetual change" — Fu Xi's Primordial Bagua establishes the cosmic foundation, while King Wen's Acquired Bagua manifests its functional applications, together forming the complete system of Yijing wisdom.

This passage primarily discusses the hexagram system of the Zhouyi (Book of Changes) and the contributions of three sages to the study of Yi (Change). It first explains the sequence of the sixty-four hexagrams: beginning with Qian (Heaven) and Kun (Earth), progressing through Kan (Water) and Li (Fire), and concluding with Jiji (After Completion) and Weiji (Before Completion). This arrangement embodies the principle of Yin-Yang opposition and transformation.

Each hexagram and its changing lines are accompanied by two types of explanatory texts: the Tuanci (Judgment), which interprets the entire hexagram (e.g., "Originating, penetrating, advantageous, and steadfast"), and the Yaoci (Line Statements), which explain individual lines (e.g., "Hidden dragon, do not act"). These symbolic texts, along with divinatory transformations, form the complete system of the Zhouyi, as organized by King Wen of Zhou—representing the "later heaven" (acquired) Yi learning.

In his later years, Confucius delved deeply into the Zhouyi, wearing out the leather bindings of his bamboo scrolls three times. He composed ten commentaries known as the Shiyi (Ten Wings), including the Xiangzhuan (Image Commentary), Tuanzhuan (Judgment Commentary), and Wenyan (Explanations of the Characters), which elucidate King Wen’s later heaven Yi learning. Meanwhile, the Xicizhuan (Great Treatise), Shuoguazhuan (Discussion of the Trigrams), and others also explain Fu Xi’s "prior heaven" (innate) Yi learning. The Xuguazhuan (Sequence of the Hexagrams) and Zaguazhuan (Miscellaneous Notes on the Hexagrams) reveal the profound mysteries of hexagram transitions and Yin-Yang opposition. These texts contain subtle teachings on the cultivation of nature (xing) and life (ming), as well as the profound principles of cosmic transformation, guiding practitioners from the acquired to the innate state and bringing Yi studies to completion.

Though Fu Xi, King Wen, and Confucius lived in different eras, each possessed extraordinary insight and together illuminated the great Dao (Way). Fu Xi’s Yi learning drew from the patterns of nature, King Wen’s inherited Fu Xi’s system, and Confucius’s synthesized both. Whether creating or interpreting, their teachings share the same origin without the slightest deviation. The formless Dao (Taiji, the Supreme Ultimate) is elusive, but the tangible hexagrams, lines, images, and numbers make it comprehensible. Thus, the sages conveyed the principles of Yin-Yang transformation through drawing hexagrams, composing judgments, and writing commentaries, providing a model for later generations of Dao cultivators.

The concluding section employs a metaphor: just as one must lift a curtain or ascend a height to see the truth clearly, practitioners require guidance from enlightened teachers. The Huoji (Records of Fire), a text of six hundred chapters, expounds the same principles, yet people often fail to reflect deeply. The author expresses reluctance to write casually, fearing the disclosure of celestial secrets might incur divine retribution, yet also worries that silence would sever the transmission of the Dao. Thus, the text is recorded with caution, adhering to the proper methods of cultivation to elucidate these profound mysteries.

This passage recounts Wei Boyang's (Master Wei) spiritual journey in composing the Zhouyi Cantongqi (The Kinship of the Three). He reflects that the true Dao cannot be comprehended without guidance from an enlightened master—even sages like Fuxi, King Wen, and Confucius relied on transmission, let alone someone like himself who lacked innate prophetic insight. Fortunately, encountering a genuine master brought sudden awakening, like lifting a curtain to ascend a high platform where everything becomes clear.

The Zhouyi (Book of Changes) contains sixty-four hexagrams, among which Qian (Heaven), Kun (Earth), Kan (Water), and Li (Fire) correspond to the furnace, cauldron, and medicinal ingredients (the foundational elements of alchemy). The remaining sixty hexagrams align with the thirty days of a lunar month, using one hexagram each for morning and evening. Over ten months, this totals six hundred hexagrams. In truth, the crux of alchemy lies in mastering the timing of fire phases (huohou), not in literally undergoing six hundred stages. Yet most people fail to delve deeply into these principles.

Understanding the Yin-Yang transformations symbolized by Kan and Li—like the alternation of sun and moon or the cycle of day and night—reveals the supreme truth. Though Master Wei grasped these insights through his teacher’s guidance, he hesitated to write them openly, fearing divine punishment for defying heaven’s will or leaking celestial secrets. Instead, he used the Zhouyi’s hexagrams as metaphors for alchemical mysteries, briefly outlining key elements like the cauldron, medicinal ingredients, and fire phases, hoping destined readers would intuitively comprehend.

The Cantongqi aligns perfectly with the intent of the three sages who composed the Zhouyi: both explore life’s origins and the profound mechanics of creation. With an enlightened master’s guidance and this text as verification, one can attain complete understanding.

The final section on the "symbolic laws of the returned elixir" (huandan faxiang) uses fifteen measures of metal (representing Yang) and fifteen of wood (representing Yin) to regulate water and fire, precisely controlling their proportions during alchemy. This embodies the essential principle of Yin-Yang balance in the art.

This passage elucidates the core principles of refining the Golden Elixir (Jindan, a symbolic term for Daoist Neidan/internal alchemy practice). It describes the dynamic interaction among three elemental forces—metal, water, and earth—which symbolize the transformative process of Jing (essence), Qi (vital energy), and Shen (spirit) within the human body.

The text first establishes metal and water as fundamental materials for alchemical work. Here, "metal" represents the body's primordial Qi (the yang line within the Kan trigram), while "water" signifies postnatal Jing (the yin line within the Li trigram). During cultivation, practitioners must use "metal" as a dike to regulate the flow of "water," much like controlling a river's current. Each element possesses fifteen units of measure, requiring precise proportioning within the inner furnace (the Dantian/energy center), with water slightly exceeding metal in quantity.

The earth element (represented by Wu and Ji soils) serves as the crucial harmonizing agent. Wu soil (primordial) resides within metal, while Ji soil (postnatal) dwells in water—each containing five units that combine to form the complete ten. These three substances intermingle miraculously within the alchemical cauldron. Below them, the true yang Qi (solar energy) steams upward, first liquefying then solidifying the substances to form the foundational "Yellow Chariot" (Huangyu), the embryonic stage of the elixir.

The scripture outlines the complete alchemical procedure: beginning with fire regulation, practitioners first apply gentle "civil fire" for nurturing, then intense "martial fire" for refinement, observing the process with the meticulous care one would give to dust on a windowpane. After twelve seasonal nodes (symbolizing celestial cycles), when the old life-form perishes, a violet-gold Reverted Elixir (Huandan) crystallizes. The resulting medicine requires only a minuscule dose (a knife-point measure called daogui) to manifest miraculous effects.

Particular emphasis lies on methodical practice: first establishing protective boundaries (the dike), then guarding the six sensory gates (eyes, ears, nose, tongue, body, and mind) to prevent Qi leakage. Internal primordial Qi must be drawn outward while external Jing must be restrained inward—their balanced union, mediated by earth's harmonizing power, completes the Great Dao of Golden Elixir cultivation.

This passage explains the principle of balancing and harmonizing the metal (Jin) and water (Shui) energies during alchemical practice. At the crescent moon phase, when Yin and Yang energies are perfectly full, the numerical value of metal Qi (representing Yang) is fifteen, and that of water Qi (representing Yin) is also fifteen. Like building a dam to control flooding, the measurements must be strictly regulated.

In practical operation, the proportions of metal and water substances must be precisely measured without the slightest error. True water (innate Yin essence) and true metal (innate Yang energy) must be perfectly balanced—neither excessive nor insufficient. The water Qi should be controlled at five parts to prevent overflow, while the metal Qi must also be maintained at five parts, adhering strictly to the initially set weight.

When metal and water achieve perfect equilibrium, true earth (the harmonizing Qi) naturally emerges to mediate between them. The five parts of water Qi in the Li trigram (symbolizing fire) correspond to Ji earth, while the five parts of metal Qi in the Kan trigram (symbolizing water) correspond to Wu earth. When metal and water merge, true earth is inherently present within them. Ultimately, Wu and Ji earth converge at the center, also amounting to five parts, combining with the other two to form the complete "three-fives" ratio (referring to the perfect proportion of metal, water, and earth, each at five parts).

This principle originates from the Hetu (an ancient mystical numerical diagram): the east is associated with three (Wood), the south with two (Fire), with Wood and Fire accompanying each other; the north is associated with one (Water), the west with four (Metal), with Metal and Water as companions. Here, special emphasis is placed on Metal and Water rather than Wood and Fire because Metal and Water resemble the physical body—the material foundation—while Wood and Fire resemble the spirit—the immaterial aspect. Just as a moving body inevitably casts a shadow, Wood and Fire naturally follow the transformations of Metal and Water.

The profound mystery of alchemy lies in this: when essence (Jing) and Qi unite, the spirit (Shen) and Qi will also transform accordingly. The three substances (metal, water, and earth) intermingle and, under the steaming influence of the sun's true fire, first liquefy and then solidify into form, becoming what is called the "Yellow Chariot" (an alternate name for the Golden Elixir). If one fails to grasp the proper firing process, the passage of time will corrupt the elixir’s nature, causing it to dissipate like dust on a windowsill.

This passage describes the process of Golden Elixir formation through the interaction of the Kan and Li trigrams (water and fire). The two energies of metal and water merge into one under the mediation of true earth, producing wondrous transformations. If the preparatory protections are thorough, the true Qi in the alchemical furnace will naturally arise. At this stage, the true Yang from the Kan trigram is drawn to replenish the true Yin in the Li trigram. The sun’s true fire from the "Northern Sea" (the essence stored in the kidneys) rises and steams upward, soon prompting the true water in the "Li Palace" (the heart’s fire) to respond—first transforming into a white liquid, and ultimately solidifying into the indestructible Golden Elixir.

This passage explains the process and methods of "Kan-Li coupling" (the union of water and fire) and "returning the elixir" (Huandan) in Daoist Neidan (internal alchemy) practice.

First, it describes how during cultivation, the original spirit (infant) and original qi (maiden) interact and circulate in the Yellow Court (middle Dantian), guided and harmonized by true intention (the yellow matchmaker). Before their union, true intention must facilitate their meeting; after union, it must guard them. At this stage, yang qi withdraws into the earth (lower Dantian), and vitality turns to stillness, like the withering and hibernation of all things in winter. The practitioner must merge spirit and qi, remaining as silent as withered wood or cold ashes. Over time, new vitality emerges—true qi (primordial energy) rises faintly like fine dust, marking the initial union of Kan and Li (water and fire) and the imminent birth of the "great medicine" (raw material for the internal elixir).

Next, it details the method of refining the "returning elixir": the medicinal substance (essence and qi) produced by Kan-Li coupling is cooked in the Kun furnace (lower Dantian). When the great medicine forms, it must be guided upward by true intention, like a "swirling wind blending all," ascending from the lower Dantian to the upper Dantian (Qian cauldron), where it gradually condenses into the elixir. This process requires repeated blending, akin to grinding herbs, using breath regulation techniques (inhaling, sipping, gathering, and sealing) to deliver the medicine to the Crimson Palace (upper Dantian). Once the elixir condenses, it must be led back to the Yellow Court (middle Dantian), where it must be tightly guarded until entering a state of profound stillness, ensuring the true yang qi does not dissipate.

Finally, it describes the manifestation of the elixir: fierce fire (intense mental focus) is used to refine it, carefully regulating the "heat" like a skilled alchemist, completing a full celestial cycle of twelve double-hours. When essence and qi are exhausted and the body appears lifeless, the spirit transforms into a violet hue—the refined returning elixir (internal elixir) resembles violet powder, and even the smallest amount (a speck the size of a knife-point) possesses miraculous potency.

This passage explains the crucial principles of "fire timing" (mental regulation during practice) and "celestial cycle circulation" (internal energy flow) in Daoist Neidan (internal alchemy) cultivation. At the pivotal moment when Yang energy begins to stir (during Zi hour, 11 PM to 1 AM) — akin to sudden underground flames erupting — one must immediately mobilize the True Fire (primordial Qi) to respond. This triggers the phenomenon of "Dragon-Tiger Union" (harmonious interaction of Yin-Yang energies), accompanied by distinctive internal resonances.

When the Great Medicine (Neidan energy) first emerges, gentle "civil fire" (subtle mental focus) nurtures its growth. As it strengthens, intense "martial fire" (forceful concentration) refines it until the elixir crystallizes. Fire timing requires precise calibration: excessive intensity scorches, while insufficient vigor fails to form the elixir. Like regulating temperature, perfect balance is essential.

The celestial cycle begins at the coccyx (Weilü point), corresponding to the Fu hexagram (first Yang line emerging). Circulating through twelve two-hour periods, the practice culminates at Wu hour (11 AM–1 PM) with "fire withdrawal" at the Niwan Palace (crown of the head), matching the Gou hexagram (first Yin line appearing). This Qian-Kun cosmic exchange repeats continuously. Through repeated "extracting lead and adding mercury" (refining Jing into Qi), one ultimately achieves complete Yin dissipation and pure Yang perfection.

At the zenith of cultivation, mundane physiology and consciousness transform entirely: turbid Yin energies vanish completely, revealing the corpse-like signs of mortal dissolution. When the Yang Spirit (pure Yang embodiment) awakens, the physical body dies while the soul transcends. As Master Guan Yinzi proclaimed, true Dao attainment manifests only when even respiration ceases. After prolonged cultivation resembling death and rebirth, the internal elixir achieves luminous completion — the supreme Purple Returned Elixir. This Golden Elixir, forged through Water-Fire refinement, appears as insignificant as dust yet holds miraculous transformative power, ultimately enabling the practitioner’s cosmic metamorphosis.

This passage elucidates the core mystery of Daoist Neidan (internal alchemy) practice—the generative principle and process of the "Reverted Elixir" (Huandan).

The opening metaphor "the cauldron recreates heaven and earth" compares the human body to an alchemical vessel, where practitioners can cosmologically recreate the universe within. The term "knife-guǐ" (Daoju), originally an ancient measuring tool for medicinal substances, here symbolizes the refined materials required for cultivation. "Gold within water" refers to the primordial Jing (essence) contained in kidney-water, while "the two soils of wù and jǐ" represent the spleen-earth and intentional mind. The entire alchemical process involves the dynamic interaction among metal (lungs), water (kidneys), and earth (spleen) to ultimately refine the Reverted Elixir.

Master Cui Xifan of the Tang Dynasty wrote in his Mirror for Compounding the Medicine: "Drink the knife-guǐ, behold heaven's ingenuity," while Lü Dongbin described in Spring in Qin Garden: "I drink the knife-guǐ myself"—both depicting the wondrous experience of ingesting the Reverted Elixir. Though seemingly born from emptiness, this elixir manifests miraculous efficacy.

The practice unfolds in two stages: First comes the "subduing and ingestion" phase, where two energies intersect at the Kun position (lower Dantian) to generate medicinal substances. Then follows the "Reverted Elixir" stage—when Yang energy first stirs, concentrated awareness gathers at the Qian cauldron (upper Dantian) to crystallize the Golden Elixir (Jindan). This mirrors how plants grow from Kun (earth) but bear fruit in Qian (heaven).

Quoting Awakening to Reality: "Produced in Kun, cultivated in Qian," the text further clarifies: while the elixir forms in the lower Dantian, its ultimate transformation completes in the upper Dantian. The entire process follows nature's patterns of Yin-Yang interaction and water-fire equilibrium.

Ultimately, the Reverted Elixir's essence lies in harmonizing Yin-Yang and balancing water-fire. Like the moon waxing and waning between lunar phases, practitioners must seize the critical moments of water-fire ebb and flow. When metallic nature returns to its original state, Yin and Yang spontaneously unite to accomplish the elixir. The alchemical methods transmitted by ancient sages—from the Yellow Emperor to the King of Huainan—all fundamentally embody this principle.

Water and fire originally shared the same source, later differentiating into two distinct substances. Within the Qian trigram (representing Heaven), a single point of Yang energy enters the Kun trigram (representing Earth) to form the Kan trigram (Water), wherein lies the True Fire of the Sun. Similarly, a point of Yin energy from the Kun trigram transfers into the Qian trigram to form the Li trigram (Fire), which contains the True Water of the Moon. These two energies—water and fire—mutually contain their origins within each other, producing infinite transformations wherein all Five Phases (Wood, Fire, Earth, Metal, Water) are fully manifested.

Water generates Wood, Wood generates Fire, Fire generates Earth, Earth generates Metal, and Metal in turn generates Water—this clockwise cycle of mutual generation follows the harmonious progression of the Hetu (the ancient cosmic diagram). Conversely, Fire overcomes Metal, Metal overcomes Wood, Wood overcomes Earth, Earth overcomes Water, and Water in turn overcomes Fire—this counterclockwise cycle of mutual restraint follows the reverse pattern of the Luoshu (another cosmic diagram). The interplay of these two cycles—one generating, one restraining—forms the foundation for the myriad transformations of the Five Phases.

In their pre-heaven, formless state, water and fire harmonize and complement one another, while in their post-heaven, manifest forms they oppose and conflict. The sun and moon in the heavens are the water and fire of the mundane world: the sun embodies the essence of fire, the moon the essence of water. On the first day of each lunar month (the new moon), when the sun and moon conjoin along the ecliptic (the sun's apparent path through the celestial sphere), this is called "conjunction." If they align perfectly, the moon obscures the sun, creating a solar eclipse. The human body follows the same cosmic patterns: most recognize that the Kan trigram symbolizes the moon, yet fail to realize that the True Water within the Li trigram is the moon's essential essence; they know the Li trigram represents the sun, but overlook that the True Fire within the Kan trigram is the sun's radiant light.

During the transition between the last day of the old moon and the first of the new, sun and moon unite like precious jade, their water and fire energies mutually containing one another. That single point of solar True Fire sinks to the deepest depths of the Northern Sea, just as the Northern Song philosopher Shao Yong described "the sun descending into the earth to unite"—in Neidan (internal alchemy) practice, this represents the mysterious state where Kan and Li (water and fire) meet in sacred communion.

When the body's yang energy (true yang) first begins to stir, it resembles the rising sun that requires gentle nurturing. At this stage, one should maintain stillness like a hidden dragon, refraining from prematurely activating this energy. Only when yang energy fully ascends—like the sun breaking over the horizon to illuminate the world—can its power be fully expressed. If true yang fails to govern bodily functions and is instead suppressed by yin energy, it's akin to northern frigid waters flooding and obscuring the sun. Even at high noon when yang energy should be strongest, its radiance would appear dimmed.

This celestial metaphor illustrates: The Kan trigram (representing kidney water) resides in the northern realm of darkness, corresponding to the midnight hour and new moon; while the Li trigram (representing heart fire) dwells in the southern realm of brightness, matching the midday sun. Water and fire (heart and kidneys) must maintain equilibrium to mutually nourish each other—an imbalance in either direction creates disharmony, much like solar and lunar eclipses where yin energy from the moon suddenly obstructs the sun's yang radiance.

Yet these describe abnormal states. Under normal circumstances, kidney water doesn't overflow nor heart fire weaken—just as the sun naturally illuminates the earth and the moon softly glows. This represents the natural interaction between water and fire, the fundamental pattern of yin-yang communion. Eclipses occur precisely when celestial bodies deviate from their ordained paths, whereas when yin and yang follow natural rhythms, their harmony resembles mutual nourishment through shared sustenance. Through these celestial metaphors of normal and abnormal sun-moon interactions, we understand the potential successes and failures in the human body's Kan-Li (water-fire) interactions, reminding practitioners to exercise careful discernment.

Regarding the essential practice of "metal returning to its nature": The primordial essence within the Li trigram (heart) is fundamentally the true water of supreme yin (also called wood liquid), while the primordial qi within the Kan trigram (kidneys) is the true fire of supreme yang (also called metal essence). Internal alchemy (Neidan) cultivation uses water-fire as foundation and metal-wood as function. As Master Guan Yinzi observed, metal and wood essentially represent water and fire in their blended states. Though metal and wood appear as two distinct substances, both originate from the pre-heaven metallic nature of the Qian trigram—this metallic nature exists pure and indestructible before life's formation. Only after conception, when the pre-heaven unified qi enters the Kun palace (physical body) transforming into the Kan trigram, must cultivation work to restore it to its original nature.

This passage elucidates the core principle of "transforming temperament" in Daoist Neidan (internal alchemy) practice. It employs the properties of metal and wood as metaphors: metal (金) symbolizes the fluctuating nature of emotional desires, while wood (木) represents the tranquil and authentic innate nature. Just as a person may have both a given name and a courtesy name—different in designation but identical in essence—so too are these aspects of human experience.

The original pure Qian Yang (heavenly innate nature) transforms into Kan water (acquired emotional desires), much like metal melting from solid to liquid. Conversely, the genuine Yin within Kun Yin (the acquired physical form) transforms into Li fire (innate spiritual awareness), akin to wood releasing energy through combustion. Ordinary people follow this transformation, allowing their desires to grow increasingly dominant and thus becoming trapped in the cycle of birth and death. Practitioners, however, must reverse this process, refining the fluid emotional desires (the metallic essence within Kan) back into pure Yang nature (the fundamental nature of Qian). This is the profound meaning of "returning the elixir" (还丹).

The text cites multiple classics to corroborate this point: The Śūraṅgama Sūtra states that just as pure gold is extracted from ore, once refined, it never reverts to its crude state; The Complete Enlightenment Sūtra affirms that the nature of gold remains indestructible. The verses of the immortal masters Lü Dongbin and Zhang Boduan also point to this principle of the "indestructible nature of gold." The author emphasizes that the myriad words in Buddhist and Daoist scriptures ultimately converge on this core teaching of "refining emotions to return to nature." Ancient sages like the Yellow Emperor prized the Golden Flower (Golden Elixir), while the Huainanzi records the preparation of autumn minerals (elixirs)—all these are different expressions of the same alchemical truth.

The crux of cultivation lies in this: when the mind is stirred by external phenomena (responsive activation), one must maintain the stillness of the original heart (serene non-movement). This skill of "preserving stillness within movement" is the essential method for returning restless emotions to the innate nature of primordial purity.

This scripture elucidates the fundamental principles of cultivating the Golden Elixir (Jindan) in Daoist practice. Since ancient times, the essence of cultivation has always revolved around harnessing that primordial golden nature (referring to the most refined primordial Qi within the human body). Whether for personal transcendence beyond the mundane world or for composing texts to enlighten others, all paths originate from this root.

Though sages throughout history have given this fundamental principle different names—the Yellow Emperor called it "Golden Splendor," Huainanzi termed it "Autumn Stone," Master Yuyang named it "Yellow Sprout," while other metaphors like "Dragon-Tiger" were also used—these varied appellations all point to the same reality. They describe the Golden Elixir forged through harmonizing the two Qi of Yin-Yang (where the dragon and tiger symbolize these complementary forces). Just as "Autumn Stone" depicts the transformative process from black to white, and "Yellow Sprout" metaphorically represents the vital energy emerging from earth, both describe the alchemical transformation of primordial Qi.

The scripture particularly emphasizes that this cultivation method should only be transmitted to spiritually gifted practitioners. The wise immediately recognize this as the refinement of primordial Qi, while the unenlightened misinterpret the metaphors—taking "Dragon-Tiger" as heterodox magic, "Yellow Sprout" as mineral-based alchemy (Waidan), or even mistaking "Autumn Stone" for urine distillation, completely missing the sacred truth. Hence the ancient saying: "The worthy may uphold this practice, the unworthy must not walk this path together"—the true Dao can only be transmitted to those capable of comprehension.

The passage repeatedly clarifies that although various elixir scriptures employ diverse metaphors and names, they all preserve the fundamental cultivation methods dating back to the Yellow Emperor's time, never intentionally using obscure language to confuse later generations. The key lies in grasping the essence of "primordial golden Qi," without being misled by the multitude of symbolic terms.

This passage discusses several key perspectives on the Daoist classic Zhouyi Cantong Qi (The Kinship of the Three). It first highlights that the core of cultivating the Great Dao of the Golden Elixir (Jindan) lies in grasping the "primordial golden nature" — the pure Yang nature of one's original being — which is the only true and essential practice, while all else is secondary.

The ancient sages attained realization through personal practice before composing texts. Though their interpretations differed, their fundamental principles were perfectly aligned, conveyed with the sincerity of face-to-face dialogue. The author emphasizes that learners must seek guidance from genuine masters, deeply study the profound principles, and repeatedly contemplate and verify them to realize that the Great Dao of the Golden Elixir is actually right before their eyes.

Two common misconceptions are clarified: First, regarding the origins of Cantong Qi, some mistakenly believe it was modeled after the Dragon-Tiger Scripture (Longhu Jing). In reality, the Dragon-Tiger Scripture is shallow in content and clearly a later forgery. Second, concerning the lineage of Wei Boyang (the attributed author of Cantong Qi), these claims are unreliable. Since the erroneous interpretations by Peng Xiao and Wang Dao during the Song Dynasty, many alchemists conflated Cantong Qi with the Dragon-Tiger Scripture, mistakenly reducing the Great Dao of the Golden Elixir to external alchemy (Waidan) practices — a lamentable deviation.

Finally, the text explains that "emulating the sages" does not specifically refer to the Dragon-Tiger Scripture but broadly denotes the ancestral masters since the time of the Yellow Emperor. It elucidates the origins of various alternate names for the Golden Elixir, such as "Golden Radiance" (Jinhua) and "Yellow Sprout" (Huangya, representing the nascent state of the elixir). The author stresses that these concepts all have classical foundations and cannot be simplistically attributed to the apocryphal Dragon-Tiger Scripture.

The Dragon-Tiger Scripture (Longhu Jing) must be an ancient transmitted text. During Wei Boyang's era (the renowned Eastern Han dynasty alchemist), people could still grasp its general meaning, but by our time it has long been lost—it absolutely cannot be the spurious Dragon-Tiger Scripture circulating in recent times.

Some may ask: What exactly do the phrases "emulating the sages" and "transmitting the teachings of the Three Sages" in the text mean? In truth, these two concepts don't contradict each other. The specialized terms like "dragon-tiger" (symbolizing Yin-Yang Qi) and "golden flower" (referring to the Golden Elixir) used in the text all derive from traditions dating back to the Yellow Emperor. Meanwhile, the three essential alchemical components—"medicinal ingredients," "furnace and cauldron," and "firing times"—indeed originate from the Yijing (Book of Changes) system established by the Three Sages: Fuxi, King Wen, and Confucius. This is beyond doubt. It also explains why statecraft and alchemical practice can mutually illuminate each other.

Two key passages prove this conclusively: The concluding lines of the middle chapter mentioning "how sages of old refined the Nine Cauldrons" explicitly indicate its connection to ancient alchemical scriptures. The final verses of the lower chapter's "Hymn Transmitting the Legacy of the Three Sages from the Great Yi" (Dayi, i.e., Yijing) even more clearly demonstrate this lineage to the Book of Changes. Significantly, neither passage mentions the Dragon-Tiger Scripture at all, showing that "emulating the sages" here refers to general principles rather than any specific classic.

The practical alchemical sections are considerably more abstruse than the first two volumes. After this explanation, the meaning becomes crystal clear—like clouds parting to reveal the sun. As for the age-old controversy about the Dragon-Tiger Scripture's authenticity, though my perspective may be limited (like viewing the sky through a bamboo tube), I dare to point it out nonetheless. After centuries when none dared speak the truth, finally setting the record straight brings immense satisfaction!

(Note: The "Three Sages" refer to Fuxi, King Wen, and Confucius; "dragon-tiger" in alchemical context symbolizes Yin-Yang Qi; "golden flower" denotes the Golden Elixir; "hidden ingestion" refers to the cultivation method of ingesting the elixir)