《易說》Vol. 4

This passage presents several key conceptual diagrams in Daoist cosmology:

The Hetu (River Chart) and Luoshu (Luo Writing) - ancient mystical diagrams said to have been revealed to Fuxi (who derived the Bagua/Eight Trigrams from them) and Yu the Great (who used them to control floods) - represent the primordial state before heaven and earth formed. The Diagram of Chaotic Ultimate (Hunji Tu) depicts the undifferentiated chaos before Yin-Yang separation, where the clear and turbid Qi had not yet parted, yet already contained all principles that would later manifest the myriad things. Like the Taiji (Supreme Ultimate) itself which doesn't manifest Yin-Yang visibly, the principles of their transformations are already latent within.

The Diagram of Primordial Ultimate (Yuanji Tu) describes an even earlier state than chaos - when pure primordial Qi congealed without form or color, existing before heaven and earth. It holds the potential for Yin-Yang transformations and serves as the source of Taiji Qi. This mysterious essence without beginning or end embodies what the Yijing (Book of Changes) calls the eternal principle of change, comprehensible only through transcendent wisdom beyond ordinary understanding.

The Diagram of Spiritual Ultimate (Lingji Tu) reveals the spiritual essence existing prior to all manifestation. It simultaneously contains infinite potentiality (miao you, "marvelous being") and absolute emptiness (zhen wu, "true nothingness"), spontaneously revealing its nature without deliberate distinction. This state transcends all dualities of form and formlessness, serving as the spiritual source of all generation.

This passage elucidates the core Daoist cultivation concepts of "Taiji" (Supreme Ultimate) and "Central Pole." The phrase "unbored yet naturally perforated" suggests one need not strive deliberately, for the primordial opportunity of creation can be spontaneously apprehended to awaken spiritual origins. As the Dao De Jing states: observing the mysteries of Dao in desirelessness while perceiving its gateways in desire—this encapsulates the essence of cultivation.

The nature of Dao is vast emptiness; only when the mind is void can it become numinously dynamic. This state of supreme numinosity constitutes the origin of heaven, earth, and all things—the source of all transformations. The Taiji diagram illustrates how the "Supreme Ultimate" unfolds gradually from numinous potency into ethereal manifestation. Untainted by Yin-Yang interference yet luminous without diminishing its essence, it contains the constant principles of Yin-Yang within seemingly chaotic changes. The upper "one" in the diagram represents Yang (odd number), the lower "two" signifies Yin (even number), while the connecting lines symbolize humanity. Born from Yang yet encompassing Yin, humans thereby mediate between heaven and earth, standing at their nexus.

Without addressing the "Primordial Ultimate" (original source), Taiji degrades into mere phenomena; without Taiji, the Primordial becomes empty abstraction. Precisely this quality—beginningless movement and stillness, mutual generation of Yin-Yang—manifests Taiji's divine function.

The Central Pole diagram reveals the most authentic state of numinous potency—Taiji's initial differentiation from unity. The originally congealed state gradually dissolves as formed elements begin circulating. Ascending Yang contains Yin within, descending Yin harbors Yang within. Stillness at its extreme becomes the root of movement; movement at its peak returns to stillness' function—an endless cyclical process. Yin-Yang should be distinguished vertically (above/below) rather than horizontally (left/right); movement-stillness signifies growth-containing-transformation rather than simple repetition. Taiji is fundamentally stable—its variations emerge through Qi's dynamic operation according to the fundamental law of mutual reinforcement between firm and yielding, never arbitrary inversion.

This scripture elucidates the principles of Yin-Yang transformation and the generation of heaven and earth. The "Diagram of Lesser Extremity" (Shaoji tu) described here depicts the nascent state of Yin-Yang: a single yang line (odd) positioned at the center with two yin lines (even) flanking its sides, while yang qi gathers and meanders below. At this stage, yang qi remains faint and life force lies dormant, hence the designation "lesser." As yang qi ascends to form heaven and yin qi descends to form earth, the primordial true qi (yi yuan zhenqi) between them begins its ceaseless circulation.

The text employs the Five Phases of water, fire, wood, and metal to explain the waxing and waning of Yin-Yang: nascent water represents tender yang qi, which grows vigorous when developing into wood; nascent fire signifies faint yin qi, which solidifies when maturing into metal. Old yang and old yin (referring to Yin-Yang at their zenith) cannot sustain further generative transformation—only through lesser yang and lesser yin (nascent Yin-Yang) can they fulfill their function of nurturing all beings.

The "Diagram of Great Yang" (Taiyang tu) reveals the essence of the sun: though solar in nature, it inherently contains yin characteristics. The sun warms all creatures through its partnership with the moon (Great Yin, Taiyin), as yang qi requires yin substance to remain stable and cohesive. While the sun's form belongs to yang, the quintessence of yin is concealed within yang. This harmonious interplay of Yin-Yang enables the eternal movement of sun and moon.

The "Diagram of Great Yin" (Taiyin tu) expounds the moon's essence: derived from the differentiation of Taiji (Supreme Ultimate), it contains two parallel yin lines with qi that is empty yet unfulfilled. This demonstrates that though lunar in nature, the moon also embodies yang attributes, forming a complementary relationship with the sun. The conjunction of sun and moon manifests the transformative principles described in the Yijing (Classic of Changes).

The moon is the concrete manifestation of Great Yin (the symbol of yin energy). Although the moon belongs to yin, its essence originates from yang qi. For the moon to illuminate all things in regular cycles, it must cooperate with sunlight—only then can yin energy maintain governance without scattering. Thus, the moon's fundamental substance is actually yang in nature, with the essence of yang qi concealed within its yin form. When yin and yang operate in harmony, the waxing and waning of lunar phases follow orderly patterns. This mutual regulation between the hidden and the visible embodies the laws of celestial and terrestrial movement. This is how the moon, by aligning with the sun, fulfills the Dao of the Changes.

The Diagram of Manifest Light uses the concrete motion of the sun and moon to elucidate the principle of illumination: the radiance formed by their interaction expresses the essence of the Changes. No symbol in the world is more evident than the sun and moon, whose eternal luminous nature reveals the true meaning of the Changes. When the sun is in the east and the moon in the west, they create brightness; when the moon is above and the sun below, they manifest the Changes' transformative flexibility. The subtlety of yin-yang transformation lies precisely in their dynamic equilibrium. The substance and function of the Changes are neither confined to the fixed positions of the Li (Fire) trigram in the south or the Kan (Water) trigram in the north, nor limited by temporal distinctions of pre-heaven and post-heaven. This quality of fluid integration is captured in the threefold meaning of the character Yi (易): as "alternation" (referring to ceaseless generation), as "constancy" (referring to unchanging principles), and as "transformation" (referring to the laws of change and adaptability). Yi manifests virtue, "constancy" manifests fundamental position, and "transformation" manifests the flow of qi—this cyclical mechanism synthesizes the laws of cosmic operation. Is this not precisely mirrored in how the sun and moon mutually generate illumination through their interplay?

The Diagram of the Three Powers employs numerical symbolism to portray heaven, earth, and humanity: the even number two superimposed upon the odd number one forms a triad representing the complete system of the three powers. Heaven begins at the zi hour (midnight), earth emerges at the chou hour (1-3 AM), and humanity is born at the yin hour (3-5 AM). Humans gather the essence of yin and yang qi, standing at the apex of the two polarities (yin-yang) to become the foremost among the three powers. Though the human body seems insignificant, it can stand between heaven and earth, forming a triad with them.

This scripture elucidates two core principles: the relationship between humanity and the cosmos, and the correspondence between the Luo Shu (an ancient mystical numerical diagram) and the Bagua (Eight Trigrams).

The first section discusses the relationship between the Dao and the cosmos. The Dao exists as an undifferentiated whole, permeating heaven and earth. As one of the myriad beings, humans constantly interact with all things through mutual resonance. When individuals cultivate their innate potential, uphold the Three Bonds (ruler-subject, father-child, husband-wife relationships), clarify the Five Teachings (ethical principles of father-child, ruler-subject, husband-wife, elder-younger, and friend relationships), harmonize all affairs, exhaustively investigate cosmic principles, and fully manifest their innate nature, they attain the realm of "life destiny." At this stage, humans achieve harmony with heaven and earth, participating in cosmic creation with efficacy comparable to the Taiji (Supreme Ultimate). The Yijing (Book of Changes) encompasses the Dao of heaven, earth, and humanity - corresponding respectively to Yin-Yang, firmness-yieldingness, and benevolence-righteousness - all ultimately unified within the Taiji.

The second section explains the correspondence between the Luo Shu and the Bagua. In the Early Heaven Bagua (the trigram arrangement attributed to Fu Xi), the Qian (Heaven) and Dui (Lake) trigrams correspond to the Greater Yang numbers 4 and 9; the Li (Fire) and Zhen (Thunder) trigrams to the Lesser Yin numbers 3 and 8; the Xun (Wind) and Kan (Water) trigrams to the Lesser Yang numbers 2 and 7; and the Gen (Mountain) and Kun (Earth) trigrams to the Greater Yin numbers 1 and 6. This numerical arrangement perfectly matches the Luo Shu configuration.

The Luo Shu's numerical arrangement positions: 9 at the top (south), 1 at the bottom (north), 3 on the left (east), and 7 on the right (west), with 2 and 4 like shoulders at upper right and upper left, 6 and 8 like feet at lower right and lower left, and 5 at the center. The Yang numbers (1, 3, 7, 9) occupy the four cardinal directions, while the Yin numbers (2, 4, 6, 8) reside at the four corners. The sequence from 1 to 9 corresponds to the generative and controlling relationships of the Five Phases (Wood, Fire, Earth, Metal, Water): 1 and 6 (Water) control 2 and 7 (Fire); 2 and 7 (Fire) control 4 and 9 (Metal); 4 and 9 (Metal) control 3 and 8 (Wood); 3 and 8 (Wood) control the central Earth; and the central Earth in turn controls 1 and 6 (Water), forming a cyclical pattern of mutual restraint.

Although the Luo Shu's numerical arrangement manifests a right-rotating sequence of mutual control, its relative positions secretly contain generative relationships: southeast 4 and 9 (Metal) generate northwest 1 and 6 (Water), while northeast 3 and 8 (Wood) generate southwest 2 and 7 (Fire). This demonstrates the interdependent dialectical relationship between generation and control.

This scripture elucidates the principle of mutual generation and restraint within Yin-Yang and the Five Phases (Wuxing). It notes that if things only restrain one another without mutual generation, the restrained element would face extinction. Thus, restraint inherently contains the potential for growth, much like the Luoshu (an ancient mystical diagram) demonstrates—restraint and generation are interdependent.

The Hetu (another ancient mystical diagram) corresponds numerically with the Bagua (Eight Trigrams). In the Later Heaven Bagua arrangement, the Kan trigram corresponds to one and six (associated with Water), the Li trigram to two and seven (Fire), the Zhen and Xun trigrams to three and eight (Wood), the Qian and Dui trigrams to four and nine (Metal), and the Kun and Gen trigrams to five and ten (Earth). These numbers align perfectly with the Hetu's arrangement, showing that the Hetu and Luoshu complement each other, and the Earlier Heaven and Later Heaven Bagua share an intrinsic connection.

In ancient times, a dragon-horse emerged from the Yellow River bearing the Hetu, on which the odd and even numbers of Yin and Yang were intricately arranged according to the natural laws of heaven and earth. Fuxi derived the Bagua from this, with the numerical sequence fully corresponding to the trigrams' meanings. Among them, one to five are the "generating numbers" (shengshu), while six to ten are the "completing numbers" (chengshu). One marks the beginning of numbers, ten their conclusion, and five represents the central number between heaven and earth, symbolizing the convergence of Yin and Yang. Yang numbers initiate growth, Yin numbers bring fulfillment, and their internal and external harmony ensures each of the Five Phases occupies its proper place.

Specifically: one multiplied by five yields six, so one and six reside together in the north (Water); two multiplied by five yields seven, so two and seven reside together in the south (Fire); three multiplied by five yields eight, so three and eight reside together in the east (Wood); four multiplied by five yields nine, so four and nine reside together in the west (Metal); five multiplied by five yields ten, so five and ten reside together in the center (Earth). These numbers pair odd with even, Yin with Yang, coexisting in harmony.

The sequence of the Five Phases' mutual generation is as follows: the one-six Water of the north generates the three-eight Wood of the east; Wood generates the two-seven Fire of the south; Fire generates the five-ten Earth of the center; Earth generates the four-nine Metal of the west; and Metal in turn generates Water, creating an endless cycle that embodies the principle of perpetual vitality. The Hetu's numbers begin in the north and rotate leftward in mutual generation, yet in their opposing positions, the one-six Water of the north restrains the two-seven Fire of the south—a relationship where restraint subtly contains the seeds of generation.

This scripture explains the principles of mutual generation and restraint among the Five Phases (Wood, Fire, Earth, Metal, Water) and the formation of the Eight Trigrams (Bagua). The south corresponds to Fire (numbers two and seven), the west to Metal (numbers four and nine), and Metal restrains the east's Wood (numbers three and eight). Yet this restraining relationship is actually contained within the generative cycle. The natural law of cosmic creation reveals that if there were only generation without restraint, all things would lose moderation, failing to manifest the complete function of heaven and earth in generating existence. Thus restraint must be contained within generation—appropriate control paradoxically fulfills the virtue of growth. This principle of "restraint serving generation" can be observed in the Hetu (the ancient cosmic diagram).

When Fuxi (Baoxi) observed celestial phenomena, he noticed a deficiency in the northwestern heavens. Using the wholeness of the Taiji (Supreme Ultimate), he supplemented this northwestern region. He drew an unbroken line (yang yao) to symbolize this heaven-mending action—this line represents the odd-numbered yang principle, embodying the substantial nature of heavenly Dao. The leftward rotation of celestial bodies and the cycle of seasons all emerge from the celestial gate in the northwest. The sage's single brushstroke was no arbitrary act but carried profound meaning.

Fuxi further observed insufficiency in the southeastern earth, so he divided the Taiji's wholeness to supplement this region. He broke a line into two segments (yin yao), symbolizing the even-numbered yin principle that represents earth's receptive quality. The alternation of cold and heat, and the distribution of mountains and rivers, all manifest through the earthly gate in the southeast. These two strokes by the creator of the Yijing (Book of Changes) similarly contain the profound principles of heaven and earth.

Finally, the interaction of the two polarities (yin and yang lines) gave birth to the Four Symbols (Greater Yang, Lesser Yang, Greater Yin, Lesser Yin), which then evolved into the Eight Trigrams (Qian, Kun, Zhen, Xun, Kan, Li, Gen, Dui), completing the cosmic diagram.

This passage describes the natural process of cosmic formation and the emergence of the Bagua (Eight Trigrams). Taiji (the Supreme Ultimate, the primordial state of the universe) contains the two energies of Yin and Yang. When these forces interact—with Yang on the left and Yin on the right—they form the Two Modes (Heaven and Earth). The continued interplay of Yin and Yang then gives rise to the Four Symbols (Taiyin, Taiyang, Shaoyin, and Shaoyang, representing the four seasons or directions). Further movement and interaction among these Four Symbols generate the Bagua: Qian (Heaven), Kun (Earth), Zhen (Thunder), Xun (Wind), Kan (Water), Li (Fire), Gen (Mountain), and Dui (Lake).

The arrangement of the Bagua is not artificially determined but emerges naturally: Qian occupies the south, Kun the north, Li the east, Kan the west, Dui the southeast, Gen the northwest, Xun the southwest, and Zhen the northeast. This configuration aligns with the inherent patterns of Heaven and Earth—the sky above and the earth below, the sun rising in the east and the moon setting in the west, mountains having their sources and rivers their destinations, spring bringing thunder and autumn bringing winds.

Before the formation of Heaven and Earth, there existed "Li" (cosmic principle), an invisible, pattern-like stage called "Wuji" (the Limitless). From Wuji emerged the undifferentiated Taiji, which then divided into the Two Modes of Yin and Yang, eventually evolving into the Four Symbols and the Bagua. Yang energy begins at Zhen (northeast), passes through Li (east) and Dui (southeast), and reaches its zenith at Qian (south). Yin energy starts at Xun (southwest), moves through Kan (west) and Gen (northwest), and gradually strengthens until it culminates at Kun (north). Yang energy begins to grow at midnight (Zi hour) and peaks at noon (Wu hour), while Yin energy starts its ascent at noon and reaches its height at midnight. This is the natural rhythm of Yin and Yang's waxing and waning.

This passage from the Yi Shuo elucidates the natural patterns of Yin-Yang transformation. It explains that the solar year begins with the winter solstice, progressing through the four seasons in orderly succession—a profound manifestation of how Yin and Yang intermingle while movement and stillness mutually transform. By comprehending how the Taiji (Supreme Ultimate) encompasses all existence, one can understand how the Two Modes (Yin-Yang), Four Symbols (lesser Yang, greater Yang, lesser Yin, greater Yin), and Bagua (Eight Trigrams) all emerge from this primordial unity, revealing the natural laws governing Qi's cyclical movements.

The text employs the "Diagram of Qian and Kun's Opening and Closing" using gateways as metaphor: the Qian trigram symbolizes open gates while Kun represents closed gates—this rhythmic alternation between opening and closing constitutes transformation, and its ceaseless cycling embodies universal connectedness. The phenomena of Yin-Yang expansion and contraction manifest not only in trigram imagery but more fundamentally within the cosmic pair of Qian (Heaven) and Kun (Earth).

Specifically: From the Zi hour (corresponding to the eleventh lunar month) when Yang first germinates, this energy gradually strengthens until reaching its zenith in the Si month (fourth lunar month) as the six undivided Yang lines of the Qian hexagram, when all things flourish abundantly. Then at the Wu month (fifth lunar month), Yin energy begins emerging, growing progressively until the Hai month (tenth lunar month) forms the six broken Yin lines of the Kun hexagram, when all creation returns to quiescence. This waxing and waning resembles parental procreation—the six lines of Qian trace Yang's complete developmental cycle from the Fu hexagram (single Yang line) to pure Qian (six Yang lines), while Kun's six lines demonstrate Yin's parallel progression from the Gou hexagram (single Yin line) to complete Kun (six Yin lines). Notably, the Tai hexagram's lower three lines form a Qian structure, and the Pi hexagram's lower three lines compose a Kun pattern, each symbolizing the preliminary formation of Yin-Yang principles.

Crucially, when Yang reaches its apex (pure Qian) or Yin culminates (pure Kun), both represent imbalanced states—absolute Yang becomes excessively rigid, absolute Yin overly yielding, neither suitable for guiding development. Thus nature operates through the principle that "extreme Yang generates Yin, extreme Yin generates Yang," creating alternating cycles where Qian lines dominate from Zi to Si months and Kun lines prevail from Wu to Hai months. This dynamic equilibrium between Yin and Yang within the cosmic framework of Qian and Kun enables the perpetual generation and transformation of all phenomena.

This scripture elucidates the principles of Yin-Yang transformation and the mysteries of the Hetu (River Chart) and Luoshu (Luo Writing). The relationship between Yin and Yang is one of mutual waxing and waning—when Yang Qi ascends, Yin Qi recedes; when Yin Qi advances, Yang Qi retreats. This dynamic equilibrium of alternating growth and decline constitutes the fundamental operating principle between heaven and earth.

Fuxi created the Bagua (Eight Trigrams) based on the Hetu (the mystical pattern said to be carried on the back of a dragon-horse). The horizontal chart demonstrates the generative principles of the trigrams, while the circular chart depicts the movement of trigram Qi. When matching trigrams with numbers, Li, Zhen, Gen, and Kun belong to one category, while Qian, Dui, Xun, and Kan form another. This is because the Yin aspects—Old Yin and Young Yin—are relatively still and constant, whereas the Yang aspects—Old Yang and Young Yang—are active and mutable.

Upon obtaining the Luoshu (the mystical pattern on the back of a divine turtle), Yu the Great established the nine-fold governance framework in the "Hong Fan" (Great Plan). These nine categories are: the laws of the Five Phases (Wood, Fire, Earth, Metal, Water), cultivation through five practices, administration through eight policies, coordination through five regulations, the sovereign standard of the Supreme Ultimate, governance through three virtues, decision-making through divination, observation of natural omens, and rewards and punishments through five blessings and six calamities. These nine categories precisely correspond to the numbers of the nine palaces, fully manifesting the laws of Yin-Yang application.

The Hetu and Luoshu complement each other like warp and weft, with the Bagua and the nine-fold framework serving as exterior and interior aspects. Generally, the warp represents constant principles, while the weft signifies transformation. These two diagrams rotate and transform into each other: when the Hetu is primary, it represents constancy while the Luoshu represents change; the reverse holds true when the Luoshu is primary. Ultimately, the movement between heaven and earth is nothing but the interplay of the two Qi—Yin and Yang. The Taiji (Supreme Ultimate), as the cosmic origin, resides at the center, while the two modes (Yin-Yang) revolve around it. The Five Phases interact and transform within this framework, giving rise to the cosmic order where warp and weft intersect, and exterior and interior correspond.

The Hetu (River Chart, the mystical diagram said to be carried by a dragon-horse) was not only used to delineate the Bagua (Eight Trigrams), but also to elucidate the "Nine Categories" (the nine great methods for governing the world). The Luoshu (Luo Writing, the mysterious patterns on a divine turtle's shell) not only explained these Nine Categories but could equally be employed to deduce the Bagua. Ancient sages simply responded to the needs of their time, establishing principles by observing these mystical diagrams. From a perspective of adaptability, when Fuxi drew the Bagua, its surface manifestation was the trigram system, yet its underlying principles resonated with the Nine Categories; when Yu the Great arranged the Nine Categories, their overt form concerned governance, yet their deep structure secretly corresponded to Bagua principles.

The numerical arrangement of the Hetu is: seven in front, six behind, eight to the left, and nine to the right. The Luoshu's layout shows: nine in front, one behind, three to the left, seven to the right, four front-left, two front-right, eight rear-left, and six rear-right. Circular patterns symbolize celestial movements, while square configurations represent earthly boundaries. Odd numbers correspond to Yin functions, even numbers to Yang operations. Fuxi and King Wen of Zhou created the Yijing (Classic of Changes) based on these principles, while Yu the Great and Jizi formulated the Hongfan (Great Plan) accordingly. This reveals these systems' fundamental unity—all phenomena in the world manifest through square and circular forms, all numerical principles derive from odd-even transformations, all natural laws emerge from dynamic and static interactions, and all sounds arise from opening and closing states. Deep investigation of these principles allows comprehension of heaven and earth's operational mysteries.

The Taiji Bagua Diagram (with accompanying illustration), when compared with Fuxi's horizontal trigram arrangement (the original Bagua sequence), clearly demonstrates the patterns of Yin-Yang distribution above and below, and the division between inner and outer trigrams. This proves that before the trigrams were drawn, the Yi's principles already existed—through them, one may penetrate the arcane mechanisms of cosmic creation.

Fuxi's Bagua Directional Diagram (with illustration) and Sequence Diagram (with illustration) reveal: Qian (Heaven), Kun (Earth), Kan (Water), and Li (Fire) occupy cardinal positions, while Zhen (Thunder), Dui (Lake), Xun (Wind), and Gen (Mountain) occupy the four corners. This constitutes the so-called "Innate (Xiantian) Bagua" arrangement. While King Wen of Zhou later developed the Acquired (Houtian) Bagua system based on this, the Innate system remains fundamental.

This passage explains the process and principles underlying the transformation of the Bagua (Eight Trigrams) from their prenatal to postnatal arrangement. The eight trigrams are divided into four cardinal positions (Kan, Li, Zhen, Dui) and four corner positions (Qian, Kun, Gen, Xun). The transition from prenatal to postnatal Bagua occurs through mutual transformations between the trigrams.

The four cardinal trigrams change their structural composition through intersection: when Qian (Heaven) intersects with Kun (Earth), it transforms into Li (Fire); when Kun intersects with Qian, it becomes Kan (Water); when Li intersects with Kan, it shifts to Zhen (Thunder); and when Kan intersects with Li, it turns into Dui (Lake). The four corner trigrams transform through positional movement: after Kun receives yang energy from Qian, it retreats to the southwest, with yin supporting yang; after Qian receives yin energy from Kun, it withdraws to the northwest, with yang pressing upon yin. Xun (Wind) follows Kun's movement to the southeast, while Gen (Mountain) avoids Qian by shifting to the northeast.

Qian and Kun act as father and mother, Kan and Li represent their functions, Zhen and Xun exercise authority, while Gen and Dui complete the transformations. Kan's structure shows yang within yin, while Li contains yin within yang—this mutual penetration of yin-yang constitutes the origin of life. The changing movements of the Bagua manifest the patterns of heaven and earth while naturally reflecting the human mind.

The text further describes how Qian, after moving from the south to intersect with Kun in the north, withdraws to the Hai position (northwest); while Kun, after moving from the north to intersect with Qian in the south, retreats to the Shen position (southwest). The Hai position belongs to the Water phase, and Shen to the Metal phase, forming the Five Phases (Wood, Fire, Earth, Metal, Water) generative cycle: Water (Kan in the north) generates Wood (Zhen in the east), Wood generates Fire (Li in the south), Fire generates Earth (Kun in the southwest), and Earth generates Metal (Dui in the west). These transformations all arise from the spontaneous workings of creation, embodying the operating principles of heaven and earth.

This passage explains the relationship between the Eight Trigrams (Bagua) orientations and the generative-conquest cycles of the Five Phases (Wuxing). The Dui trigram, positioned in the west, corresponds to Metal, which generates Water. While Earth normally occupies the central position, it governs all four directions, hence the Qian, Kun, Gen, and Xun trigrams all relate to Earth positions.

The Kun trigram represents Yin Earth, absorbing residual Qi from Fire to prevent excessive coldness, thus enabling it to generate Metal. The Gen trigram represents Yang Earth, utilizing residual Qi from Water to avoid excessive dryness, thereby nourishing Wood. Qian's Yang Metal thrives through Earth's nourishment, functioning as the "father" that first generates Water. Xun's Yin Wood, cultivated by Earth, serves as the "mother" that generates Fire.

When Metal and Water mutually generate, the Qian trigram centrally governs the vital Qi. When Fire conquers Metal, the Kun trigram centrally governs the conquering Qi. Though the transformations of the Five Phases are limitless, the principle of perpetual regeneration lies herein—the cycles of generation, conquest, and transformation mirror the Taiji's (Supreme Ultimate) cyclical flow, embodying nature's ceaseless dynamism.

The text then discusses three types of Bagua diagrams: Fu Xi's basic orientation diagram, along with the horizontal, circular, and square diagrams created by Shao Yong (Shaozi) of the Song dynasty. These diagrams share the characteristic of "emerging from the center." The horizontal diagram begins with Qian and ends with Kun, yet the actual Yin-Yang transformations originate from Zhen and Xun—the trigrams representing Yin and Yang's initial emergence. The sequence progresses from Zhen and Xun to Kan and Li, then to Gen and Dui, and finally to Qian and Kun, illustrating the principle that "diagrams arise from the center."

Splitting the horizontal diagram vertically creates the circular diagram, while overlapping the trigrams forms the square diagram. The circular diagram's periphery has eight sections, with Zhen and Xun serving as central connectors. The square diagram features eight horizontal and vertical sections, again with Zhen and Xun as pivotal hubs. This "center" resembles heaven's foundation and the moon's abode—the core of the sixty-four hexagrams. In human consciousness, it marks the boundary between stillness and movement; in phenomena, it represents the root of all transformations. Such is the profound mystery underlying the prenatal (Xiantian) Bagua's positioning.

This passage elucidates the generative principles of the sixty-four hexagrams in the Book of Changes and their relationship with cosmic operation patterns. The diagram illustrates the dynamic interaction of firm and yielding lines (Yin-Yang interplay), revealing the fundamental law of how the eight trigrams generate one another—the alternating movement of Yin and Yang, the mutual stimulation of firmness and yielding, which constitutes the essential principle of all transformations within the Taiji (Supreme Ultimate, the cosmic origin).

The text notes that celestial bodies move in perfect circular orbits, ceaselessly revolving leftward around the earth day and night. The North and South Poles remain fixed, forming a configuration where the northern hemisphere is elevated while the southern descends. Within this process, the two Qi (energies) of Yin and Yang interact: Yang Qi ascends from the east, while Yin Qi descends from the west; the southern hemisphere follows the rising Yang Qi with a leftward pull, and the northern hemisphere follows the descending Yin Qi with a rightward pull. Though external phenomena appear endlessly varied, grasping the "One" (the fundamental law) enables mastery over the whole. Returning to inner stillness, even the most extensive principles can be summarized by this "One." Truly comprehending nature's governing principle (the law of Wuwei, or non-action), one realizes that the sixty-four hexagrams inherently lack fixed forms, and the three hundred eighty-four lines have no predetermined positions—while the hexagram sequences may appear ordered, the Li-Qi (principles and energies) they embody transcend sequence. Yin and Yang are movement and stillness; movement and stillness are Yin and Yang. They can be expressed through the most wondrous symbols, compared to the most refined phenomena, manifesting as square or round, infinitely mutable.

The second section explains, through seasonal diagrams, how the Book of Changes numerical principles are derived through reverse deduction. For instance, before the Yang pole (Yang aspect) interacts, the Qian (Heaven) hexagram has yet to form. When a single Yang line appears above, Qian takes shape, though the Dui (Lake) hexagram remains unseen. Yet its emergence becomes inevitable—one need not wait for a Yin line above the Yang to recognize Dui, for Qian itself implies Dui's eventual appearance. Similarly, before the lesser Yin (Yin aspect) interacts, the Li (Fire) hexagram is unborn. When a Yang line appears above to form Li, though Zhen (Thunder) remains latent, Li already foretells Zhen's inevitable generation. This deductive method reveals the necessary laws of Yin-Yang waxing and waning.

This scripture explains how the sixty-four hexagrams of the Book of Changes (Yijing) correspond to seasonal climatic changes throughout the year. The progression from the Xun hexagram (5th) to the Kun hexagram (8th) follows the same principle: just as we know spring inevitably gives way to summer, summer to autumn, and autumn to winter, through the interconnection of Qi (vital energy) and the blending of Shen (spirit), one can anticipate the cyclical rotation of the four seasons.

Specifically, the text aligns solar terms with hexagrams: the Fu hexagram corresponds to the winter solstice (mid-Zi month), the Yi, Zhun, and Yi hexagrams to minor cold (beginning of Chou month); the Wuwang, Lin, and Jiaren hexagrams to major cold (mid-Chou month); the Zhen and Ge hexagrams to the beginning of spring (beginning of Yin month)... This pattern continues through thirty-two hexagrams corresponding to solar terms from winter solstice to summer solstice, all belonging to the established systems of Zhen, Li, Dui, and Qian hexagrams.

From the Gou hexagram (summer solstice, mid-Wu month), the Daguo, Ding, and Heng hexagrams correspond to minor heat (beginning of Wei month)... until the Kun hexagram (winter solstice, mid-Zi month). These remaining thirty-two hexagrams belong to the Xun, Kan, Gen, and Kun systems, representing hexagrams yet to manifest.

Particular emphasis is placed on eight key solar terms (spring equinox, autumn equinox, summer solstice, winter solstice, and the four seasonal commencements), each corresponding to two hexagrams. For instance, the Zhen hexagram (initial Yang emergence) and Ge hexagram jointly correspond to the beginning of spring; the Li hexagram (initial Yin emergence) and Song hexagram to autumn's commencement; the Li hexagram (latent Yin) and Kui hexagram to summer's beginning; the Kan hexagram (concealed Yang) and Qian hexagram to winter's onset. The spring equinox corresponds to hexagrams showing balanced three-Yang and three-Yin lines with Yang energy positioned below.

(Note: The term "Qi" (炁) refers to vital life energy, "hexagram Qi" denotes natural energies corresponding to hexagram configurations, and the "thirty-two hexagrams" division reflects the ancient method of categorizing the sixty-four hexagrams into two groups of thirty-two each based on Yin-Yang principles.)

This scripture primarily elucidates the correspondence between the patterns of Yin-Yang transformation and seasonal nodes (jieqi), the Eight Trigrams (Bagua), as well as the principles of musical temperament (lülü) and the mutual generation of Yin and Yang.

Regarding seasonal nodes: When Yin energy (qi) resides below, it marks the Autumn Equinox. When the first Yang (incipient Yang energy) emerges beneath five Yin layers, it signifies the Winter Solstice. Conversely, when the first Yin appears beneath five Yang layers, it indicates the Summer Solstice. The cyclical changes of the four seasons align with the movement of the Eight Trigrams—leftward rotation follows the pre-heaven sequence of already-generated Yang numbers, while rightward rotation corresponds to the post-heaven sequence of yet-to-be-generated Yin numbers. This encapsulates the profound mystery of the Book of Changes (Yijing).

The Yin-Yang Musical Temperament Diagram reveals the alternating patterns of Yin-Yang and the generative principles of musical tones. The Qian trigram (representing Heaven), as the leader of the Eight Trigrams, pairs with the Huangzhong pitch (the foundational tone of the twelve temperaments), commencing from the Zi position (due north). This marks the beginning of harmonious interaction between Heaven and Earth. The birth of Yang at the Zi hour (midnight) constitutes the fundamental origin of all creation. The Kun trigram (representing Earth), as the ultimate Yin, follows the "interval-of-eight" generation principle (the tonal generation rule) corresponding to the Linzhong pitch, starting from the Wei position, symbolizing the return of all things to their roots and destiny.

Yang branches (Zi, Yin, Chen, Wu, Shen, Xu) belong to the Qian trigram system. Among these, the Eldest Son (Zhen trigram), though temporarily assuming the father's role at the Wu position, still originates from Zi. The Middle Son (Kan trigram) begins at Yin, while the Youngest Son (Gen trigram) starts at Chen. Yin branches (Chou, Hai, You, Wei, Si, Mao) belong to the Kun trigram system, with the three Daughter trigrams following their mother's movement: the Eldest Daughter (Xun trigram) begins at Chou, the Middle Daughter (Li trigram) at Mao, and the Youngest Daughter (Dui trigram) at Si.

Special note: The Xun trigram (Eldest Daughter) does not commence from its mother's Wei position but rather from the opposing Chou position within its native palace. This signifies that though the Eldest Daughter belongs to Yin, her energy gradually strengthens—thus she submits internally to her husband (Yang) while externally inheriting the maternal lineage. The Li trigram resides pre-heaven at Mao (east), symbolizing sunrise illumination; the Dui trigram resides pre-heaven at Si (southeast), representing water returning to marshlands. The Kan trigram (Middle Son) aligns closely with the Li trigram (Middle Daughter), as the Yin position marks the "birthplace of fire," where Wood and Fire mutually generate to enhance vitality. The Gen trigram (Youngest Son) resonates with the Dui trigram (Youngest Daughter), embodying the harmonious interaction between mountain and marsh, and the mutual attraction of affections. Yang energy is inherently strong and self-sufficient, requiring no external support to stand firm.

The yin-soft nature requires attachment to other things to take form, hence all things have their root. The numbers three and eight represent Wood (among the Five Phases), with eight being the number of all things' generation. The Eight Trigrams (Qian, Kun, Zhen, Xun, Kan, Li, Gen, Dui) total eight, with each generating the next at eight intervals—their meanings and categories all derive from this. Whether it's the inhalation and exhalation of Qi, opening and closing, or coming and going, none escape this numerical pattern.

To elaborate: Huangzhong (one of the twelve pitch pipes, corresponding to the midnight hour) generates Linzhong (corresponding to the hour of Wei), Linzhong generates Taicu (corresponding to the hour of Yin), Taicu generates Nanlü (corresponding to the hour of You), Nanlü generates Guxian (corresponding to the hour of Chen), Guxian generates Yingzhong (corresponding to the hour of Hai), Yingzhong generates Ruibin (corresponding to the hour of Wu), and Ruibin generates Dalü (corresponding to the hour of Chou). These all represent the process where Yang Qi descends to generate Yin Qi, and Yin Qi ascends to generate Yang Qi. Yang Qi begins at the midnight hour (Zi), while Yin Qi starts at the hour of Chou. Yang Qi actively initiates and rises, while Yin Qi naturally responds and settles. Though called "generation at eight intervals," this actually reflects the alternation of Yin-Yang and the cyclical principle of the Three Harmonies (the union of Heaven, Earth, and humanity).

First came Heaven and Earth, then Water and Fire emerged; with Water and Fire came mountains and marshes; and with mountains and marshes came thunder and wind. Thus, in the Prenatal Bagua arrangement, Qian (Heaven), Kun (Earth), Kan (Water), and Li (Fire) occupy the four cardinal directions, while Zhen (Thunder), Xun (Wind), Gen (Mountain), and Dui (Marsh) reside in the four intermediate directions—revealing the sequence of Yin-Yang generation.

Ancient scholars studying musical temperament and calculating tones first established the standard pitch of Huangzhong as their foundation. Thus, at the midnight hour of Zi (winter solstice), when Yang returns, the pitch pipes begin with Huangzhong as the root of all affairs. The Huangzhong pitch pipe measures nine inches, derived from the square of nine (81). All pitch pipe values are multiplied by nine because nine represents the ultimate Yang number. When Yang reaches its peak, it generates wind; wind produces sound through movement, creating harmonious tones—hence the use of nine. Larger numbers generate downward, while smaller numbers generate upward. The generative number never exceeds eight, and the incremental number never surpasses three. Three is the generative number of the East (Wood among the Five Phases), embodying the principle of the Three Powers (Heaven, Earth, and humanity). From one comes two, two generates three, and three generates all things—three being the pivot of all transformations. Eight is the fulfillment number of Wood Qi, representing the eight winds (from all directions). From two comes four, four becomes eight, and eight evolves into sixty-four (the hexagrams formed by doubling the trigrams)—eight being the number of infinite transformation. This is the principle of mutual generation, increase, and decrease. In downward generation, the actual number doubles while the rule takes three; in upward generation, the actual number takes four while the rule also takes three—all upward generations follow the three-part loss and gain method (a tuning technique in temperament theory).

This passage explains the generative sequence of the five musical notes (Gong, Shang, Yu, Jue, Zhi) in ancient Chinese music, along with the formation principles of the twelve-tone temperament system.

The generative order of the five notes follows: the Gong note produces the Shang note, Shang produces Yu, Yu produces Jue, and Jue produces Zhi. Although each of the twelve two-hour periods (Shichen) features variations of these five notes, all adhere to the fundamental pitch standards of the twelve-tone system.

The text then details the generation process of the twelve tones: the Huangzhong pitch pipe, measuring nine inches, produces the Linzhong tone (six inches) through "descending generation" (lowering by a semitone). Linzhong then generates Taicu (eight inches) through "ascending generation" (rising by a perfect fifth). This sequential generation continues with precise fractional calculations, ultimately forming the complete twelve-tone system.

Particular attention is given to the principles of Yin-Yang transformation: for instance, when Yang Huangzhong generates Yin Linzhong, it represents one Yang generating two Yin; when Linzhong produces Yang Taicu, it shows two Yin generating three Yang, and so the cycle continues. A special case occurs with the Ruibin tone: six Yin generates one Yin. Although theoretically Yin shouldn't produce Yin, when musical tones descend to their lowest extreme, they must naturally rebound upward—demonstrating the Daoist principle of reversal at the extreme. Similarly, when Zhonglü's six Yang generates one Yang, it follows this same transformative pattern.

These musical generation processes not only conform to mathematical precision but also subtly correspond with the natural laws of Yin-Yang waxing and waning, forming the foundational framework of ancient Chinese music theory.

This passage explains the principle of the "three-part loss and gain method" in ancient Chinese music theory, using the concept of Yin-Yang transformation to elucidate the laws governing musical tone generation.

When Yang energy reaches its zenith, a subtle Yin energy emerges—just as when Yang is at its peak, Yin already begins to consume it. This reveals the profound mystery of Yin-Yang mutual transformation and the alternation between fullness and emptiness. The variation of musical tones follows this same principle.

The text details the calculation methods for five ancient musical tones (from the twelve-tone system): Huangzhong, Taicu, Guxian, Ruibin, and Yize. Taking the Huangzhong pitch pipe as an example: its standard length is nine inches, with the number eighty-one (9×9) corresponding to the Gong tone. Divided into three parts of twenty-seven each—this represents the limit of triple-nine numerology. When no further increase is possible, reduction becomes necessary. By subtracting one-third and retaining two-thirds, we obtain fifty-four, which generates the Zhi tone.

The Taicu pitch pipe measures eight inches (8×9=72, corresponding to the Shang tone). Divided into three parts of twenty-four each, the number becomes too large, necessitating the subtraction of one-third while keeping two-thirds, yielding forty-eight to produce the Yu tone. The Guxian pipe measures seven inches (7×9=63, corresponding to the Jue tone). Divided into three parts of twenty-one each, the number becomes too small—further reduction would disrupt tone generation. Thus when reaching the Jue tone, the process must halt, marking a turning point in tonal transformation.

The Ruibin pipe measures six inches (6×9=54, corresponding to the Zhi tone). Divided into three parts of eighteen each, the number becomes critically small. Continued reduction would collapse the five-tone system, so one-third must be added instead—accumulating eighteen to seventy-two to generate the Shang tone. The Yize pipe measures approximately 5.3 inches (5×9=45 plus remainder totaling forty-eight, corresponding to the Yu tone). Divided into three parts of sixteen each, the number becomes so minimal that augmentation becomes mandatory despite initial reluctance.

These calculations demonstrate ancient wisdom in using mathematical precision to determine pitch, achieving tonal transformation through exact proportional adjustments that subtly mirror nature's rhythms of Yin-Yang waxing and waning.

This scripture primarily expounds on the transformations of Yin-Yang, the generation of musical tones, and essential cultivation methods. It mentions that through mathematical calculations (where one divides into sixteen, accumulating to sixty-four numbers), one can deduce the variations of musical tones. The production of the "Yu" tone (one of the ancient five tones) is related to the opening and closing of Yin-Yang. Yin and Yang transform into each other through the increase and decrease of numbers: when numbers are abundant, Yang Qi weakens and Yin Qi arises; when numbers are few, Yin Qi weakens and Yang Qi arises. This mutual waxing and waning reflects the natural progression and retreat of Yin and Yang.

The movement patterns of Yin and Yang differ: Yang Qi governs ascent, while Yin Qi governs descent. When Yin generates Yang, it manifests as upward and forward movement; when Yang generates Yin, it manifests as downward and backward movement. These ceaseless changes of ascent, descent, opening, and closing are fundamentally the mutual resonance between Qi (energy) and form. It is akin to how musical tones distinguish their pitch and clarity through the waxing and waning variations of long and short pipes (the "Lü" and "Lü" pitch standards).

The later section introduces the crucial cultivation concepts of "Heavenly Root" (Tian Gen) and "Moon Cavern" (Yue Ku). The Heavenly Root lies between the Kun hexagram (pure Yin) and the Zhen hexagram (the initial birth of Yang), symbolizing the sprout of Yang Qi nurtured at the peak of Yin. The Moon Cavern lies between the Qian hexagram (pure Yang) and the Xun hexagram (the initial birth of Yin), symbolizing the sprout of Yin Qi nurtured at the peak of Yang. Practitioners, by grasping these pivotal moments of Yin-Yang transformation (such as "reaching for the Moon Cavern with the hand" or "treading upon the Heavenly Root with the foot"), harmonize Yin and Yang across the "Thirty-Six Palaces" (acupoints throughout the body), achieving the harmonious state where "all becomes spring."

Finally, it is noted that the Book of Changes (Yijing) serves as a guide for aligning with the rhythms of Heaven in human affairs. The movement of all things generates Yang Qi, while stillness generates Yin Qi—this is the fundamental principle. Pure movement or stillness belongs to the material level, while the state where movement and stillness interpenetrate belongs to the realm of Shen (spirituality), and their fusion is the realm of Qi. To maintain balance between movement and stillness is to grasp the profound mystery of the Heavenly Root and Moon Cavern.

This passage elucidates the principles of Yin-Yang transformation. The "space between Qian and Xun" (referring to the directional alignment between the Qian and Xun trigrams in the Bagua) represents the state where Yang Qi reaches its zenith and Yin Qi begins to sprout, akin to the moon's first rising position. Yin and Yang are fundamentally one primordial Qi (Yuanqi), merely manifesting different states of motion and stillness: in movement it appears as Yang, in stillness as Yin, perpetually alternating without end.

When Yang Qi flourishes, it doesn't mean Yin Qi is entirely absent—it merely remains subtle; likewise, thriving Yin Qi harbors latent Yang. Extreme prosperity inevitably declines, while minimal presence necessarily grows. The "space between Kun and Zhen" (between the Kun and Zhen trigrams) signifies the sprouting state where Qian's stillness reaches its limit and begins to stir—called the "Heavenly Root." Conversely, the "space between Qian and Xun" denotes the budding state where Kun's closure culminates before opening—termed the "Lunar Grotto" (the cave of the nascent moon). Just as deeper plant roots produce lusher foliage, and the moon's dark side precisely reveals its true form—this explains the origin of these names.

The opening-closing movements of Yin-Yang Qi nurture all things. Humans, positioned between heaven and earth, can grasp the mysteries of waxing and waning Yin-Yang by "standing on the Heavenly Root and reaching into the Lunar Grotto," thereby comprehending the subtleties of breath cultivation. The mentioned "Thirty-Six Palaces" refer to combinations of Bagua lines: solid Yang lines (strong strokes) count as one, broken Yin lines (soft strokes) as two—twelve Yang palaces plus twenty-four Yin palaces total thirty-six.

Maintaining acute sensory awareness allows one to perceive creation's patterns through the interplay of Zhen (thunder) and Xun (wind) trigrams, symbols of dynamic transformation. When the mind becomes empty and luminous—free from attachments and thoughts—it naturally aligns with heaven-earth operations. Then all thirty-six palaces harmonize: Yang palaces avoid scorching heat, Yin palaces shun bitter cold, everywhere brimming with springlike vitality.

All growth originates from the heart—simultaneously life's root and wisdom's grotto. By neither harming the root nor obscuring clarity, one fills the heart with vernal energy that impartially nourishes all things. The heart emerges with Zhen (expansion) and withdraws with Xun (contraction). Maintaining this ceaseless generative rhythm attains a state of flawless purity.

The interplay of Yin and Yang between heaven and earth constitutes the fundamental rhythm of the cosmos, with the movements of the sun and moon serving as its most vivid manifestation. How then do we observe these cosmic transformations? By tracking the sun's daily ascent and descent, and the moon's cyclical waxing and waning - these celestial patterns reveal the hidden dynamics of Yin's recession and Yang's emergence.

While the sun's radiance remains constant, the moon's phases undergo perpetual transformation. Ancient sages thus mapped lunar cycles onto the Bagua (Eight Trigrams) to chart Qi's fluctuations: During the moonless "dark day" (Hui), we find correspondence with the Kun trigram (pure Yin), representing Yin's ultimate expression. Yet when Yin reaches its zenith, Yang is born - the first sliver of the new moon (Fei) on the third lunar day signals Yang's initial stirring, corresponding to the Zhen trigram as Kun's Yin Qi begins to recede.

At the first quarter moon on the eighth day, dual Yang energies emerge under the Dui trigram, while Zhen's influence fades. The full moon (Wang) on the fifteenth day brings triple Yang fulfillment through the Qian trigram (pure Yang), with Dui's presence diminishing. Notably, neither Yin nor Yang completely vanishes here - only when Yin fully retreats does Yang climax, inevitably reversing course.

Eighteen days after fullness, the first Yin emerges through the Xun trigram as Qian's Yang begins its withdrawal. The last quarter moon on the twenty-third day witnesses dual Yin energies under the Gen trigram, replacing Xun's influence. By month's end, the moonless dark returns with triple Yin through Kun, completing the cycle as Gen recedes. This natural alternation proceeds without artifice - a cosmic dance of mutual transformation.

"Recession" (Xiao) describes lower forces supplanting higher, like erosion; "growth" (Xi) signifies upper forces nourished from below, like flourishing. As Yang retreats, Yin advances; where Yin departs, Yang returns - an endless cycle of mutual succession. Crucially, neither principle undergoes abrupt transformation before reaching its limit - fundamental change occurs only at the point of exhaustion, revealing the cosmos' generative mystery.

In Neidan (internal alchemy) practice, aligning with these natural rhythms constitutes "advancing Qi" (beneficial for cultivation), while forcing contrary to nature becomes "leaking Qi" (depleting vital energy). Advancing Qi fosters growth, leaking Qi induces decline, and when decline reaches its extreme...[original text breaks off here, describing the critical point of Yin-Yang transformation]

This passage elucidates the cyclical patterns of Yin-Yang waxing and waning. When things reach their extreme, they inevitably reverse—just as the end of dissolution marks the beginning of renewal. This dynamic interplay manifests vividly in the hexagrams of the Yijing (Book of Changes): when the way of noble individuals flourishes, petty people decline; when petty people gain influence, noble individuals withdraw. This exemplifies the mutual transformation of Yin and Yang.

The hexagrams Guai (Resolution) and Bo (Splitting Apart) demonstrate this clearly: starting from Kun (Pure Yin), the gradual ascent of a single Yang line transforms it into Guai; beginning with Qian (Pure Yang), the gradual descent of a single Yin line turns it into Bo. Dissolution erodes from below upward, while growth sprouts from above downward. This cyclical alternation reveals the patterns of transformation between the "young and old" stages of Yin and Yang (referring to their different developmental phases).

Among the sixty-four hexagrams, most have tangible imagery, but Kan (Water) and Li (Fire) lack concrete forms because the essence of Yin-Yang lies deeply concealed within them. Internally, Yin and Yang cooperate; externally, they resonate with each other. Dissolution harbors the seeds of renewal, and renewal secretly contains dissolution—such subtle transformations operate endlessly.

The hexagrams illustrate this concretely:

Kun (☷), originally pure Yin, transforms into Zhen (☳) when a single Yang line emerges, causing Kun's characteristics to wane. As Zhen's single Yang line continues to grow, the appearance of a second Yang line turns it into Dui (☱), and Zhen's characteristics fade. When Dui's Yang energy expands further to three full Yang lines, it becomes Qian (☰). The reverse is also true: when Qian (Pure Yang) develops a single Yin line, it changes to Xun (☴); as Xun's Yin energy grows, it becomes Gen (☶); and when Gen's Yin energy reaches fullness, it returns to Kun (☷).

This pattern of transformation can be summarized as follows: Zhen's (☳) single Yang line arises from the extreme transformation of Kun's (☷) Yin energy; Dui's (☱) two Yang lines develop from Zhen; Qian's (☰) pure Yang represents the culmination of Dui's progression. The growth of Yin follows the same logic: Xun's (☴) single Yin line emerges from Qian's transformation; Gen's (☶) two Yin lines develop from Xun; and Kun's (☷) pure Yin is the ultimate outcome of Gen's progression.

Finally, the arrangement of the first thirty hexagrams in the "Upper Classic" of the Yijing forms a Yang-dominant system, with Qian, Kun, Kan, and Li as its core. The combinations and sequences of these hexagrams vividly embody the cyclical patterns of Yin-Yang waxing and waning.

This passage elucidates the hierarchical relationships and functional patterns of the Qian (Heaven), Kun (Earth), Kan (Water), and Li (Fire) trigrams from the Yijing (Book of Changes).

Qian and Kun represent Heaven and Earth respectively, serving as the sovereign trigrams (primary hexagrams). Qian (☰) embodies pure Yang, while Kun (☷) embodies pure Yin. Notably, Yang itself contains further differentiation—its first half represents Yang-within-Yang, and the latter half Yang-within-Yin. The Kan (☵) and Li (☲) trigrams function as ministerial trigrams (subordinate hexagrams), their roles varying according to positional contexts.

The text particularly emphasizes Qian's governing position among the sixty-four hexagrams. Though the Yijing sequence begins with Qian, Kun, and Zhun in succession, the true hierarchy manifests in structural relationships: Qian's six solid lines above Kun's six broken lines symbolize Heaven covering and Earth supporting. This vertical correspondence embodies the profound meaning of "Heaven esteemed above, Earth humble below"—mirrored in ancient rulers' ceremonial robes (upper garment over lower skirt) modeled precisely after this Qian-Kun structure.

In practical application, the six hexagrams following Qian and Kun—Zhun, Meng, Xu, Song, Shi, and Bi—all represent different manifestations of the Kan trigram (☵). While Kan's essential form appears at the end of the upper canon hexagrams, its functional expressions permeate these initial six. Each contains Kan's elemental structure: Xu (☵☰) shows Kan above Qian, Meng (☶☵) displays Gen above Kan, demonstrating Kan's operational presence through these derivative forms.

The term "two bodies" refers to the combinatorial relationship between upper and lower trigrams, while "repeated Kan" denotes its complete form (☵☵). The other six hexagrams represent Kan's functional differentiations. This analysis unveils the Yijing's inherent logical framework—beneath the seemingly simple hexagram sequence lies a philosophical system of orderly hierarchy and distinct functional manifestations.

This passage explains the special status of the Kan (坎) hexagram in the Yijing (易经) and its relationship with other trigrams. Among the Eight Trigrams (Bagua), Kan (representing water) ranks second but actually holds the most honored position because it embodies the qualities of yang strength and central correctness. Other trigrams like Xun (巽), Li (离), and Dui (兑) lean toward yin, while Zhen (震) and Gen (艮) belong to yang but are not pure. Only Kan maintains a harmonious balance of yin and yang and occupies the central position.

The text uses familial relationships as a metaphor: Zhen resembles the eldest son, while Kan is likened to the legitimate heir (the son born to the primary wife), as Kan’s structure is upright, whereas Zhen is slightly skewed. Through the analysis of the paired hexagrams Zhun (屯) and Meng (蒙), we can see that Kan’s six-line structure actually incorporates the characteristics of Zhen and Gen. When Zhun and Meng are viewed together, their combined imagery is hidden within the six lines of Kan itself; conversely, when unfolded, Kan’s imagery can manifest as the two hexagrams Zhun and Meng.

The hexagrams in the upper part of the Yijing primarily depict the three yang lines of Qian (乾, representing heaven) giving rise to the three trigrams Zhen, Kan, and Gen, without the interference of yin lines. This symbolizes the state of the world at its inception, where yang energy ascends while yin energy remains latent—much like spring in the yearly cycle or dawn in the daily cycle. The author employs the concepts of "manifestation" (见) and "latency" (伏) to illustrate this: when Kan is manifest, Li remains hidden; when Zhen is manifest, Xun remains hidden; and when Gen is manifest, Dui remains hidden.

Finally, the sequence of Zhun and Meng is explained: in Zhun, yang energy arises from the bottommost line and ascends to the middle position, while in Meng, yang energy starts from the middle and rises to the topmost line. This reflects the upward progression of yang energy from Zhen (bottom line) to Kan (middle line) and then to Gen (top line), perfectly corresponding to the pure yang nature of Qian’s three lines. The significance of Kan lies precisely in its position as the central line, embodying the middle harmony.

This passage explains the principle of Yin-Yang interaction in the hexagram transformations of the Book of Changes (Yijing). First, Yang energy descends to combine with the lower line of the Zhen hexagram (representing thunder) and ascends to unite with the upper line of the Gen hexagram (representing mountain), forming the pure Qian (Heaven) hexagram composed of three Yang lines. The Zhun and Meng hexagrams take their positions after Qian and Kun (Earth) to govern the development of phenomena precisely because they embody this Yin-Yang union.

The Xu and Song hexagram pair is formed by the upper and lower bodies of Qian combining with Kan (Water). The Shi and Bi hexagram pair results from Kun following Qian to interact with Kan. Here we observe a sequence: Xu precedes Song because Kan actively combines with Qian first, while Shi precedes Bi as Kun takes the initiative to unite with Kan. This sequential relationship reflects the hierarchical dynamics between Yin and Yang: though both Qian and Kan belong to Yang, Qian holds superior status, so Kan comes to unite with it like a son following his father; Kun as Yin actively joins with the Yang hexagram Kan, resembling a mother yielding to her son.

From these six hexagrams, we see that Kan inherits and manifests the core energies of Qian and Kun. The first half of the Book of Changes (the "Upper Classic") initially reveals the nature of Yang within Yang. By the middle section, Yin and Yang begin interweaving, shown through Qian and Kun's interaction producing the six offspring hexagrams, where the waxing and waning patterns of Yin-Yang emerge. The initial arrangement with Qian in the south and Kun in the north transforms after the Tai hexagram's single exchange, moving Kun to dominate the southwest while Qian retreats to the northwest. Here Kan's influence weakens while Li (Fire) takes precedence, hence the Tongren and Dayou hexagrams follow immediately.

By the conclusion of the Upper Classic, Kun becomes dominant with Qian following; Li activates while Kan recedes—demonstrating the quality of Yin within Yang. As for the Dui (Lake), Xun (Wind), Gen, and Zhen hexagrams that dominate the "Lower Classic," none could form independent hexagrams in the Upper Classic's early stages. They had to attach themselves to Qian, Kun, Kan, or Li like guests relying on hosts. Only with the emergence of the Sui, Gu, Yi, and Daguo hexagrams...

This passage analyzes the patterns of Yin-Yang transformation in the first thirty hexagrams of the Book of Changes (Yijing), using the relationship between host and guest as a metaphor for the waxing and waning of these forces. The first fifteen hexagrams are predominantly Yang (Yang within Yang), while in the latter fifteen, Yang gradually weakens and Yin strengthens (Yin within Yang).

Among the first fifteen hexagrams, host trigrams representing heaven (Qian, Yang) and earth (Kun, Yin), water (Kan, Yang) and fire (Li, Yin) predominate (25 instances), while guest trigrams representing thunder (Zhen, Yang) and mountain (Gen, Yin), wind (Xun, Yin) and marsh (Dui, Yin) appear less frequently (5 instances). Here, Qian outnumbers Kun (10:7) and Kan surpasses Li (6:2), demonstrating Yang's dominance.

The latter fifteen hexagrams show the opposite pattern: host trigrams decrease (13 instances) while guest trigrams increase (17 instances). Among guest trigrams, Zhen (thunder) appears more than Xun (wind) (6:3), and Gen (mountain) exceeds Dui (marsh) (5:3), indicating that while Yang begins to wane, it hasn't yet been completely subdued by Yin. However, Kun starts to outnumber Qian (5:2) and Li surpasses Kan (4:2), revealing Yin's gradual ascendancy.

Notably, the hexagrams Sui, Gu, Yi, and Daguo represent situations where guest trigrams form independently, symbolizing "traps" set by Yin. The paired hexagrams Lin and Guan demonstrate Yin's surpassing of Yang, while the subsequent sequence of Bo, Fu, Wuwang, and Daxu shows Kun (Yin) taking the lead with Li (Yin) presiding, forcing Qian (Yang) into submission.

The text concludes that this Yin-Yang dynamic manifests through host-guest interactions: Kun combining with Gen forms the Qian hexagram (Modesty), while Zhen combining with Kun creates the Yu hexagram (Contentment). Qian marks the conclusion of the first fifteen hexagrams, and Yu initiates the latter fifteen, symbolizing how Yang's ascension stabilizes dominance while its retreat permits Yin's gradual growth.

This passage primarily explains the evolutionary patterns of host-guest relationships between Yin and Yang in the Book of Changes (Yijing). When the movement of Yin-Yang Qi becomes imbalanced, the host-guest relationship undergoes transformation. Initially, there is merely an interaction between host and guest (as seen in the Qian and Yu hexagrams), where the guest still relies on the host. As the imbalance intensifies (in the Sui and Gu hexagrams), the guest becomes independent.

This transformation is reflected in the combinations of trigrams: at first, the Kun (Earth) trigram interacts with Gen (Mountain) and Zhen (Thunder) trigrams (Qian and Yu), where the host-guest relationship remains manageable. Later, Kun interacts with Dui (Lake) and Xun (Wind) trigrams (Lin and Guan), entering entirely into the guest’s domain—even to the point of the guest overtaking the host. By the time of the Wuwang and Daxu hexagrams, the Qian (Heaven) trigram’s position is inverted, as if shoes and hats are worn backward.

The latter part of the Yijing emphasizes viewing the hexagram sequence through the lens of change. Just as after the Tai hexagram, the positions of Qian and Kun are reversed between north and south, the latter part of the Yijing actually begins with the "Six Offspring Trigrams" (derived from Qian and Kun)—Dui and Gen, Zhen and Xun—and concludes with Kan (Water) and Li (Fire), illustrating the mutual generation and restraint among these six trigrams. The earlier part of the Yijing describes the interaction of Qian and Kun (the "parent trigrams") through primordial Qi (Xiantian), while the latter part depicts the interaction of the six offspring trigrams through conditioned Qi (Houtian). This mutual restraint paradoxically leads to mutual generation.

Notes:

1. The "Six Offspring Trigrams" refer to Zhen (Thunder), Xun (Wind), Kan (Water), Li (Fire), Gen (Mountain), and Dui (Lake), all derived from the Qian and Kun trigrams.

2. Xiantian refers to the original state of the cosmos, while Houtian refers to the manifested world.

3. The hexagrams mentioned—Qian, Yu, Sui, Gu, etc.—are all from the 64 hexagrams of the Yijing.

This passage elucidates the organizational principles governing the hexagram sequence in the latter half of the Classic of Changes (Yijing), using familial hierarchy and spatial orientation as metaphors. The Qian (Heaven) and Kun (Earth) hexagrams resemble parents presiding at the central hall, while the other six hexagrams (Kan, Li, Zhen, Gen, Xun, Dui) stand like married children arrayed beneath them to left and right, forming a natural order of precedence. This explains why the second part begins with the Xian and Heng hexagrams and concludes with Jiji and Weiji.

In the first half of the classic, Qian, Kun, Kan, and Li play leading roles, but become supporting characters in the latter portion. With the exception of the paired terminal hexagrams Jiji-Weiji, none can stand independently as pairs—they must attach themselves to principal hexagrams. The sole exception is the Jin-Mingyi pair, which, positioned at the end of the first section with Kun as host and Li as auxiliary, retains enough residual energy to form its own configuration.

Three hexagram groupings illustrate these patterns: The Jin-Mingyi pair and the Jiaren-Kui pair both demonstrate Kun's governance over the three daughters (Xun, Li, Dui), situated between Dun, Dazhuang, Jian, and Xie hexagrams. Here, Dui and Xun envelop Kun and Li, maintaining Kun's dominance with Li in secondary position.

Observe the relationship between the Xian-Heng pair and the Sun-Yi pair: the former shows Dui-Xun enclosing Gen-Zhen, while the latter reverses this with Gen-Zhen surrounding Dui-Xun. These four hexagrams interweave through the first half of the latter section like protective walls shielding the principal hexagrams. Across all twelve hexagrams, yin hexagrams lead while yang hexagrams respond—the defining characteristic of the classic's second half.

The core structure emerges clearly: In Guai-Gou, Dui-Xun envelop Qian; in Cui-Sheng, they envelop Kun; in Kun-Jing, they surround Kan; and in Ge-Ding, they encase Li. Through this alternating embrace by Dui and Xun above and below, the text achieves its comprehensive arrangement of the four cardinal hexagrams—Qian, Kun, Kan, and Li.

In the Book of Changes (Yijing), the Eight Trigrams (Bagua) are divided into upper and lower sections. The upper section is dominated by Qian (Heaven) and Kun (Earth), while the lower section is led by Dui (Lake) and Xun (Wind). Structurally, in the upper section, the Qian and Kun trigrams each appear twelve times, signifying their supreme status. Similarly, in the lower section, Dui and Xun also appear twelve times, indicating their equally elevated position. This demonstrates that Dui and Xun in the lower section hold a rank comparable to Qian and Kun in the upper section.

From a directional perspective, the Qian trigram occupies the due south position, with Dui and Xun flanking it on either side. When Heaven and Earth interact harmoniously (as seen in the transition between the Tai and Pi hexagrams), Kun moves to the south while Qian shifts to the north. At this point, Dui and Xun remain aligned with Kun in the upper position, with no other trigrams able to match their standing. This is why, in the lower section, certain hexagrams feature only Dui and Xun, excluding Zhen (Thunder) and Gen (Mountain).

In the Early Heaven (Xiantian) arrangement of the Eight Trigrams, the Supreme Ultimate (Taiji) generates the Two Modes (Yin and Yang), which in turn produce the Four Images (Greater Yang, Lesser Yin, Lesser Yang, and Greater Yin). These then give rise to the Eight Trigrams. Among them, the Qian trigram (representing Heaven) and the Dui trigram (representing Lake) both originate from the Greater Yang image. Qian is formed by adding a Yang line to Greater Yang, while Dui is formed by adding a Yin line. Thus, Qian and Dui stand side by side within the Greater Yang image, unmatched by any other trigram. This explains why Qian dominates the upper section while Dui leads the lower section, and why their hexagrams are placed at the forefront of the sixty-four hexagrams.

In fact, the significance of the Dui trigram is not limited to the lower section. In the latter half of the upper section’s twelve hexagrams, the Sui and Gu hexagrams are already positioned at the very beginning. By observing the sequencing patterns of the hexagrams, much of this logic becomes clear.

The final portion of the lower section features the four primary trigrams: Zhen, Gen, Xun, and Dui. Rather than appearing at the start of the lower section, they are placed at the end because the opening of the lower section symbolizes Yang within Yin (dynamic function), while the conclusion represents Yin within Yin (static essence). This reflects the principle that essence resides within while function manifests outwardly. However, the four trigrams—Zhen, Gen, Dui, and Xun—...

This passage explains the transformations of Yin-Yang and the relationship between substance (体) and function (用) in the hexagrams of the I Ching. The Zhen hexagram (representing thunder) and Gen hexagram (representing mountain) belong to Yang hexagrams, symbolizing the upward movement of Yang Qi; while the Xun hexagram (representing wind) and Dui hexagram (representing marsh) belong to Yin hexagrams, embodying the downward convergence of Yin Qi. These four hexagrams exist independently yet interact harmoniously, forming various combinatorial patterns.

The Jian, Guimei, Zhongfu, and Xiaoguo hexagrams manifest the harmonious union of Yin and Yang; the Feng, Lü, Huan, and Jie hexagrams demonstrate their interwoven states. These represent the static structural aspects of the hexagrams rather than their dynamic applications. The latter half of the lower canon pertains to Yin-within-Yin, revealing the quiescent essence.

The Zhongfu, Xiaoguo, Jiji, and Weiji hexagrams fully display the interlaced structure of the six offspring hexagrams (Zhen, Gen, Xun, Dui, Kan, Li). The same principle applies to the Yi, Daguo, Kan, and Li hexagrams in the upper canon. The Qian (pure Yang) and Kun (pure Yin) hexagrams stand at the beginning of the sixty-four hexagrams as fundamental substances, while the six offspring hexagrams conclude the sequence, illustrating the progression from substance to function.

From the hexagram sequence perspective: the upper canon begins with Kan (water) and Zhen (thunder) representing spring; concludes with Li (fire) symbolizing summer; the lower canon starts with Dui (marsh) embodying autumn; and ends with Kan (water) signifying winter—thus mapping the cyclical rhythm of the four seasons. The upper canon, Yang-dominant, concludes with Li to suggest Yang's culmination generating Yin; the lower canon, Yin-dominant, ends with Kan implying Yin's extremity producing Yang. This law of Yin-Yang transformation enables the perpetual circulation between the upper and lower canons.

When examining the hexagram sequence, one must grasp the characteristics of complementary firmness and softness, the unity of internal and external, and comprehend their symbolic meanings through cyclical contemplation. The entire system embodies the core I Ching philosophy of Yin-Yang mutual rooting and the dynamic interchange between substance and function.