《崔公入藥鏡註解》

"Commentary on Master Cui's Mirror for Compounding the Elixir" – A Vernacular Interpretation:

The study of immortal cultivation is not something ordinary people can easily comprehend. It requires individuals of profound spiritual roots and unwavering determination, or those with exceptional insight and wisdom to practice. What exactly does a cultivator need to do? Externally, one must investigate the laws governing the movement of heaven and earth; internally, one must penetrate the mysteries of body and mind. Yet even so, just as Confucius (Xuanni) would never have uttered his "admiration for the dragon" without Laozi's personal guidance, or as Śākyamuni (Qutan) could hardly have attained transcendent wisdom unless he were an incarnation of ancient sages—so too are Daoist practitioners as numerous as hairs on an ox, while those who attain the Dao remain as rare as unicorn horns. The crucial difference lies in whether one receives authentic transmission.

The essence of immortal cultivation lies in returning to the origin through the dual cultivation of nature and life (xingming shuangxiu): taking the primordial qi (the universe's fundamental energy) as the foundation of the elixir, while employing postnatal breath to regulate the firing process. Refining one's nature with true fire enables the spirit (shen) to become indestructible; refining life with true fire allows the Dao's energy to endure eternally. Transforming the turbid mortal body into a body of pure yang leads to the state of supernatural freedom and harmony with heaven and earth—is this not truly marvelous?

Observing contemporary immortal seekers, though numerous, I find their discussions of true methods often fragmented and deviating from orthodox transmission. Master Cui's Mirror for Compounding the Elixir encapsulates the essence of numerous alchemical classics in just eighty-two concise lines. Presuming upon my limited understanding, I've appended commentary after every four lines based on oral instructions from my master, revealing their hidden mysteries to guide future practitioners. Readers who study this attentively will surely receive divine inspiration leading to enlightenment. Should anyone doubt my annotations, let them know Master Cui's original text is wholly trustworthy—by practicing accordingly and completing the transformation of nature and life, the great work of immortal cultivation will be accomplished.

[Main Text Commentary]

"Primordial qi, postnatal qi—those who obtain it remain perpetually as if intoxicated":

Primordial qi is the universe's most fundamental energy (yuan shi zu qi), residing in the human body's central axis, deep within the dantian at the position called "Celestial Heart" (tianxin). The key to immortal cultivation lies in gathering this primordial qi as the foundation for the Golden Elixir (jindan).

This scripture discusses the movement of "postnatal Qi" (Hou Tian Qi) in Daoist Neidan (internal alchemy) practice and its correspondence with celestial rhythms of the sun and moon.

On cultivating postnatal Qi:

Postnatal Qi refers to the vital energy circulating through respiration. During exhalation, one connects with the celestial root (Baihui point at the crown), while inhalation links with the earthly root (Yongquan point at the soles). Exhalation resembles a dragon's hum summoning clouds, inhalation mimics a tiger's roar stirring winds. The breath should flow continuously like unbroken silk, returning to the primordial ancestral Qi (the most fundamental life energy), blending internal and external energies to ultimately form the "returned elixir" (Huan Dan, the internal alchemical achievement). Advanced practitioners may experience warmth in the Dantian (energy center), limb comfort, and ecstatic trance states. The Daode Jing's reference to "the valley spirit never dying" describes this mystical cultivation state.

On celestial movements:

The ecliptic path governs the heavens - the sun advances one degree daily, while the moon travels over twelve degrees. Lunar-solar conjunctions occur during new moon (Shuo) and dark moon (Hui) phases. The moon's cyclical transformations are:

• First quarter moon (8th day) - balanced Yin-Yang
• Full moon (15th day) - Yang energy culmination
• Third quarter moon (23rd day) - balanced Yin-Yang
• Dark moon (30th day) - Yin energy culmination

Practitioners should visualize the body as a microcosm:

• The physical form symbolizes Qian-Kun (heaven-earth)
• Kidney Qi (Kan) and heart Qi (Li) serve as alchemical ingredients
• Yin-Yang energies must be regulated like celestial movements

The crucial method involves balancing "Wu-Ji" (central spleen-earth) and "Geng-Jia" (metal-lung and wood-liver energies), representing essential Neidan techniques.

(Note: The mentioned Fu and Gou hexagrams from the Yijing symbolize Yin-Yang transformations, used here as metaphors for internal energetic changes in alchemical practice.)

This scripture elucidates the core principles and practical methods of Daoist Neidan (internal alchemy) cultivation, interpreted in modern terms as follows:

The crux of cultivation lies in mastering "fire timing" (the regulation of intention during practice) - something ordinary people employ daily without realizing it. In truth, the operational principles of the human body mirror those of heaven, earth, sun and moon. During alchemical practice, one must harmonize the body's Yin and Yang Qi like the celestial movements of sun and moon, allowing them to intermingle within the Dantian (the cauldron), where through refinement they coalesce into the "sacred embryo" (the nascent form of the internal elixir).

The text mentions "Wu-Ji" representing the central earth element, which serves as the crucial mediator between metal, wood, water and fire. Just as metal generates water and wood generates fire, without the harmonizing function of central earth, Yin and Yang cannot achieve balance. Practitioners must guide Yang Qi (Wu earth) to ascend from the kidneys (Kan position) while directing Yin Qi (Ji earth) to descend from the heart (Li position), thereby returning the four manifestations to their origin.

"Geng-Jia" respectively represent western metal (emotions and desires, symbolized as the tiger) and eastern wood (original nature, symbolized as the dragon). Ordinary people are often driven by desires, much like a rampaging tiger that harms one's fundamental nature. Cultivators must employ the "Yellow Matron" (symbolizing true intention) to harmonize emotions and nature, facilitating the union of dragon and tiger within the Dantian.

The text's mention of the "Magpie Bridge" refers to crucial energetic passages: the upper bridge at the tongue (connecting the Conception and Governing vessels) and the lower bridge at the perineum. During practice, when true intention guides Jing (essence) and Qi upward to the Niwan (upper Dantian), this is called "ascending the Magpie Bridge"; its return to the lower Dantian is termed "descending the Magpie Bridge." The "Yellow Matron," "infant," and "maiden" are all metaphors representing true intention, kidney essence, and heart-mind respectively.

Finally, the text emphasizes aligning practice with celestial timing - just as stars influence tides, the body's Qi and blood circulation follow natural rhythms. These cultivation terms are all metaphors describing the intrinsic energetic transformations within the human organism.

This passage elucidates several key points of Daoist Neidan (internal alchemy) practice:

The metaphor "heaven responds to stars, earth responds to tides" is first explained: during cultivation, the internal transformative work relies on the power of the Celestial Stem (the Big Dipper) to propel the process, while its external manifestation resembles the upward surge of genuine Qi (vital energy) like an incoming tide. The alchemical scriptures state that the method itself isn't difficult—the crucial point lies in accurately harnessing the energies of heaven and earth.

Next, it details the concrete method of elixir refinement: one must refine the body's true lead (original Jing/essence) and true mercury (original Shen/spirit). When the Gui-water (kidney essence) begins to generate, the practitioner must mobilize the breath (Xun-wind) and employ the fire of the Dantian (Kun-palace) to elevate the yang energy within the kidneys (yang within Kan) to supplement the yin of the heart (yin within Li). This creates the harmonious interaction of Yin-Yang, forming the Golden Elixir. This process requires repeated tempering to purify the Jing and Qi, ultimately coalescing into the immortal embryo of the Golden Elixir. The Scripture on Salvation (Duren Jing) describes this as harmonizing the Qi of the five organs and concentrating the hundred spirits.

Thirdly, it emphasizes the critical importance of fire regulation: during elixir refinement, the water (Jing) in the cauldron must not dry up, nor should the fire (Shen) in the furnace grow too cold. Like boiling medicine, one must master the heat—too strong will scorch it dry, too weak proves ineffective. Precise control of breath and intention is essential to achieve the perfect balance of water and fire (Yin-Yang equilibrium), as the slightest deviation will prevent elixir formation.

Finally, it explains the relationship between lead (original Jing) and mercury (original Shen): one must cause the original Jing to ascend while making the original Shen descend—the two mutually restrain yet must never separate. This resembles driving dragons and tigers—one must direct their movement without allowing them to run wild. This constitutes the pivotal factor determining success or failure in alchemical practice.

This passage elucidates the core methodology of Daoist Neidan (internal alchemy) practice, using metaphorical language to describe the movement of Yin-Yang energies within the body.

The text employs alchemical symbolism: "lead" represents the authentic Yang Qi (dragon) concealed in kidney water, while "mercury" signifies the genuine Yin Qi (tiger) contained within heart fire. During cultivation, practitioners mobilize the energy of the spleen (represented by Wu-Earth and Ji-Earth) to guide the kidney's Yang Qi upward to the Niwan Palace at the crown of the head (the dragon emerges from fire), while directing the heart's Yin fire downward to the lower Dantian (the tiger returns to water). This process requires the balanced application of "civil and martial fires": martial fire (intense mental focus) propels Yang Qi upward, while civil fire (gentle awareness) guides Yin Qi downward.

The poetic verses of Zhang Ziyang (a renowned Song dynasty Neidan master) vividly depict this process: taming the fierce white tiger (Yin energy) and the unruly azure dragon (Yang energy) until they achieve equilibrium, ultimately refining the Golden Elixir. The crux of cultivation lies in the principle that energy originates in the lower Dantian (Kun position) and crystallizes in the upper Dantian (Qian position). The method involves: igniting Yang Qi from the lower Dantian, using martial fire to propel it upward along the Governing Vessel to the crown, then guiding it back downward to the Dantian in repeated cycles of refinement.

Key principles emphasized include:

1. "Born in Kun, planted in Qian" – energy generates in the lower Dantian and consolidates in the upper Dantian

2. "Utmost sincerity follows natural law" – practice requires devout concentration aligned with cosmic principles

3. "Gathering the Five Phases, uniting the Eight Trigrams" – harmonizing the energies of the five organs (Five Phases) and integrating the body's Qi dynamics (Eight Trigrams)

These represent secret transmission formulas from ancient alchemical masters, requiring sincere practice to fully comprehend. The entire process mirrors the natural patterns of Heaven-Earth interaction and the operations of Yin-Yang and the Five Phases, achieving union with the Dao through the purification and transformation of internal energies.

This passage elucidates the core principles of Daoist Neidan (internal alchemy) practice, using the Bagua (Eight Trigrams) and Wuxing (Five Phases) to explain the mysteries of energy circulation within the human body.

It begins with the fundamental laws governing heaven and earth. The eight trigrams—Qian (heaven), Kun (earth), Kan (water), Li (fire), Zhen (thunder), Xun (wind), Gen (mountain), and Dui (marsh)—combined with the Five Phases (Metal, Wood, Water, Fire, Earth), constitute the basic cosmic principles. The essence of alchemical practice lies in "stealing" celestial energies—where "stealing" implies subtle acquisition, "seizing" denotes active appropriation, "accumulating" means gathering, and "merging" refers to integration. These techniques require oral transmission from master to disciple through esoteric instructions.

The concrete practice method involves: When internal Qi (vital energy) becomes active, one must immediately close sensory gates (blocking wind passages), collect the shen (spirit) by sealing the mountain gates, and circulate celestial energies like the Big Dipper's rotation. Through each inhalation and exhalation, one gathers the righteous energies of heaven and earth. By inverting the Five Phases and harmonizing the eight trigrams' energies, one ultimately condenses the "sacred embryo" within the Dantian (earth cauldron). Fifteen minutes of such practice yields effects equivalent to a year of natural cosmic cycles—embodying the principle that "when the human heart aligns with the celestial heart, the inversion of yin-yang occurs in moments."

The human body undergoes 13,500 breath cycles daily, each secretly absorbing cosmic energies. Prolonged practice transforms the mundane physical form into pure yang substance, achieving mastery over materialization and dematerialization at will.

Key emphasis is placed on the interplay of "true water" and "true fire":

• True water corresponds to the northern Kan trigram, manifesting as the kidneys containing a spark of true yang (fire)
• True fire corresponds to the southern Li trigram, manifesting as the heart containing droplets of true liquid (water)

Though water and fire naturally separate, they require mediation through the central spleen earth (Wu-Ji) to make true fire ascend and true water descend, merging in the Dantian. This "water-fire harmony" generates the Golden Elixir, conferring longevity.

The conclusion notes that water's fluidity and fire's combustibility manifest concretely within the body—practitioners can verify this through direct experience. Saliva represents water while Dantian warmth manifests fire; their spontaneous fusion demonstrates successful cultivation.

This passage from the Annotations on Cui Gong's Mirror for Compounding the Medicine explains the fundamental principles and methods of Daoist Neidan (internal alchemy) practice:

Water must reside above to descend and nourish, while fire must remain below to ascend and blaze—this reflects the natural movement of water and fire within heaven and earth. The same principle applies to Neidan cultivation within the human body, where these phenomena can be personally verified.

Here, the terms "nature and life" (xingming) do not refer to ordinary Shen (spirit) and Qi (vital energy). "Nature" (xing) denotes the primordial Yuanshen (original spirit, fundamental consciousness), while "life" (ming) signifies the primordial Yuanqi (vital life force). The union of nature and life represents the original state of being prior to manifestation, whereas the circulation of spirit and Qi pertains to their functional expressions in the conditioned world. Practitioners seeking to achieve "luminous spirit and stabilized vitality" must first gather the "lead from the watery region"—the primordial Yuanjing (essential essence) stored within the kidney water.

The so-called "lead from the watery region" refers to how the Kun hexagram (pure yin) transforms into the Kan hexagram (kidney water) through the influence of the Qian hexagram (pure yang), with the Kan water containing the Qian metal (primordial essence). Like a mother carrying a fetus, this spark of true yang lies concealed here. When the body manifests signs of the "living midnight" (huo zishi, the stirring of primordial yang qi), one must immediately gather it. As Master Zhang Ziyang instructed, "When lead emerges with the gui-water, gather it urgently"—this requires using intention that is neither clinging nor neglecting to guide the fire (heart-mind) in urging the metal (essence) to move. This is the "fire forcing metal to move in reverse rotation," where heart-fire descends to illuminate kidney-water, causing the essence-qi to reverse course and ascend.

Master Yunfang (Zhongli Quan) said: "The gate that gives me life is also the door to my death—how many are truly awake to this?" These lines point precisely to this "metal within water" (essence within the kidneys), the crucial element for longevity. As alchemical scriptures state: "Search diligently for this true lead—the single flavor of metal within the Hua Pool's water." This conveys the same meaning.

The key to practice lies in comprehending the "mysterious pass single aperture" (xuan'guan yi qiao), the gateway where primordial qi manifests. The work of "returning to the root and restoring life" (guigen fuming) must be accomplished through the circulation through the three passes (tailbone, spine, and jade pillow). At the stage of restoring life, one must concentrate the spirit-intent at the "sea bottom" (perineum), using true fire to gently steam the essence until it transforms into qi. This qi is then gradually drawn up from the tailbone, ascending along the spine directly to the Muddy Pellet Palace (upper dantian), where the union of dragon and tiger refines qi into spirit. When the spirit resides in its original palace at the crown, the vision of "ten thousand spirits paying homage" appears. Hence the saying: "Pierce the tailbone to connect with the Muddy Pellet" (fully opening the governing vessel).

The secret verse of Fire Master Wang Zhenjun states: "Penetrate the three spinal passes to reach the crown, riding flower-adorned deer through clouds," while the Yellow Court Scripture advises: "If you wish not to die"—both references point to this alchemical process.

This passage elucidates the essential principles of Daoist Neidan (internal alchemy) practice. It begins by emphasizing that the foundation of cultivation lies in returning to the original state of stillness, as stated in the Dao De Jing: "Returning to the root is called stillness; stillness is called returning to one's destiny."

The text employs the metaphor of the "true bellows" (zhen tuoyue) to describe the human respiratory system: the "bellows" (tuo) represents the lungs as a windbox, while the "pipes" (yue) symbolize the airways. Just as inhalation and exhalation circulate Qi (vital energy) within the body, keeping the Dantian (energy center) warm, this mirrors the Dao De Jing's observation: "Is not the space between heaven and earth like a bellows?"

The "true cauldron and furnace" (zhen dinglu) refers to the core of alchemical practice: the cauldron symbolizes Qian (heaven, representing innate nature), while the furnace represents Kun (earth, representing life force). During cultivation, one must mobilize internal Qi (the bellows) to gather Jing (essence, the "medicine") into the cauldron. First, "martial fire" (intense mental focus) is used to fuse Shen (spirit) and Qi, forming the "returned elixir" (huandan, the internal elixir). Then, "civil fire" (gentle awareness) nurtures it, achieving the dynamic equilibrium of movement and stillness—the state of "presence within absence, absence within presence."

The passage further illustrates with the allegory of the "yellow matron" (huangpo) and the "maiden" (chanü): the yellow matron signifies intentionality (associated with the central Earth phase), while the maiden represents kidney Jing (associated with the Metal phase). Practitioners must guide essence with awareness, gently raising it from the coccyx up the Governing Vessel to unite with the heart-mind. Master Cui employed this metaphor specifically to help ordinary people comprehend the process of refining the elixir, echoing the Wuzhen Pian's teaching: "The maiden's journey follows its own course"—essence circulates along defined pathways.

(Note: "Martial fire" denotes intense meditative focus; "civil fire" indicates gentle sustaining awareness; the "river chariot" refers to the circulation of essence through the Conception and Governing Vessels; the "Southern Palace" signifies the heart; and the "metal lord" represents the original spirit.)

This scripture elucidates the methods and principles of Daoist Neidan (internal alchemy) cultivation:

During practice, one must seize the opportune moment, beginning with brief sessions that gradually extend until the energy settles in the "Yellow Matron" (referring to the middle Dantian). Like marrying off a daughter, this process refines the "Golden Duke" (the Jing-essence stored in the kidneys) into the "Aged Youth" (pure Yang Qi).

All twelve two-hour periods (Shichen) of the day are suitable for cultivation, with the key lying in the application of intention. Intention arises from the heart-mind's nature, representing "True Earth" (the harmonizing Qi that balances Yin and Yang). The day divides into Yin-Yang phases: from Zi (11 PM-1 AM) to Si (9-11 AM) belongs to Yang, while Wu (11 AM-1 PM) to Hai (9-11 PM) pertains to Yin. The Zi hour corresponds to the body's nascent Yang energy, while Wu hour marks the birth of Yin.

Water and fire (heart and kidneys) reside in north-south opposition, wood and metal (liver and lungs) separate east-west. To unite these Four Symbols (four energetic forces), one must employ intention as the mediating bridge. Heaven and Earth's creative moments pass fleetingly, so practitioners must maintain constant vigilance—activating the "fire" (propelling Jing-Qi circulation) during movement of intention, and gently nurturing (preserving energy) during stillness.

"Drinking the knife and tablet" refers to ingesting the elixir: the knife symbolizes metal within water (kidney Jing-essence), while the tablet represents the genuine earth of Wu-Ji (the transformative Qi of spleen and stomach). During alchemical refinement, one gathers kidney Jing-essence, then through spleen-stomach transformation drives it upward to the Muddy Pellet Palace (upper Dantian at the crown), where it condenses into nectar-like true liquid descending into the Yellow Court (middle Dantian).

"Observing heaven's ingenuity" means discerning the Dao's operational patterns, grasping the body's internal rotation of seven-starred energies like the Big Dipper, thereby seizing creation's pivotal opportunities. As Lü Dongbin's poetry states, one must master the profound mechanism of the Dipper's revolutions.

Discerning the lunar phases (critical Yin-Yang transition points) operates on multiple levels: annually, the winter solstice marks Shuo (Yin's exhaustion and Yang's birth) while the summer solstice signifies Wang (Yang's culmination and Yin's emergence); monthly, the new moon is Shuo and the full moon Wang; daily, Zi hour is Shuo and Wu hour Wang; in practice, Qi activation at the coccyx (Weilü point) is Shuo while energy saturation at the crown is Wang; advancing the fire during Zi hour is Shuo, while withdrawing the tally during Wu hour is Wang.

This scripture expounds the core principles and practical methods of Daoist Neidan (internal alchemy) cultivation, focusing primarily on the transformations of Yin-Yang, the harmonization of lead and mercury, and the dual cultivation of nature and life (xingming shuangxiu).

First, it explains the principle of Yin-Yang dynamics: A dull, drowsy state resembles dusk (mu), while a clear, awakened state resembles dawn (zhao). Just as the "Zhun" hexagram in the Yijing (Book of Changes) represents the initial emergence of Yang qi at dawn, the "Meng" hexagram symbolizes the first stirrings of Yin qi at dusk. When the six lines of a hexagram are inverted, they form another hexagram—this mirrors the ascent and descent of Yin-Yang energies in the human body, which follow the same patterns as the movements of heaven and earth. Those who grasp this principle can achieve longevity like the immortals Zhongli Quan and Lü Dongbin.

The key to cultivation lies in:

1. "Recognizing floating and sinking": Mercury (representing the heart-mind) is light and floats upward, while lead (representing kidney essence, jing) is heavy and sinks downward. The secret of alchemy is to make the sinking lead rise and the floating mercury descend, achieving the harmonious interaction of Yin and Yang.

2. "Understanding host and guest": Life energy (ming) is the host, while innate nature (xing) is the guest. The body gives rise to life energy, and life energy gives rise to innate nature. In cultivation, one must "let life energy be the host and innate nature the guest," maintaining awareness in daily life.

In actual practice, lead and mercury (essence, qi, and spirit) must blend within the furnace and cauldron of the Dantian (energy center), like host and guest sharing a room. One must maintain constant vigilance throughout the day to attain the state of unity between heaven and humanity. When cultivation reaches a certain stage, true fire (energy) will spontaneously arise below the navel, and sweet dew (saliva) will naturally descend from the crown of the head—these are wondrous states that occur naturally. As Confucius said, "The Dao cannot be left for even a moment," and Celestial Master Zhang Xujing (Tianshi) also advised, "When the spirit (shen) emerges, it must be drawn back." Practicing day and night in this way will naturally lead to the formation of the "spiritual embryo" (inner elixir, neidan).

Regarding the timing for gathering the medicine (harvesting innate qi):

One must seize the moment when Yang qi first emerges (such as during the zi hour, midnight), carefully regulating the breath. At this time, the senses should be closed (entering seclusion), allowing the true qi to circulate through the three passes (tailbone, spine, and jade pillow) before returning to the Dantian after completing a full cycle. This process brings indescribable joy, but one must exercise caution to avoid excessive excitement, which could disrupt progress.

This scripture particularly emphasizes the importance of balancing Yin and Yang and cultivating both nature and life (xingming shuangxiu). Through breath regulation and mental concentration, one gathers innate qi to ultimately form the inner elixir. All processes must follow natural principles without force or contrivance.

This passage explains the key principles of Daoist Neidan (internal alchemy) practice in modern terms:

On receiving Qi (primordial energy):

During the processes of "advancing the fire" (active cultivation) and "retracting the tally" (concluding the session), practitioners must maintain absolute mental purity and single-minded focus. Even the slightest distraction or error could undo all previous efforts. One must be as vigilant as defending a fortress against breaches.

On mastering the "fire times" (cultivation timing):

At the critical moment when "dragon and tiger meet" (the harmonious interaction of Yin and Yang energies), extreme caution is required as if crossing a log bridge. Some mistakenly believe cultivation should follow personal whims—this reveals their ignorance of the subtle transformations involved.

When the "fire times" reach completion:

Miraculous signs will appear in the Dantian (energy center)—such as "yellow sprouts" (embryonic form of the Golden Elixir) and "white snow" (pure Yang energy)—resembling an infant taking form. At this stage, forceful striving should cease, transitioning to gentle nurturing. Continuing aggressively would damage the elixir. When the Golden Elixir matures, practitioners experience "illumination in the empty chamber" (a state of luminous clarity), demanding even greater reverence.

On breath regulation:

Breathing should become subtle, continuous, and prolonged, leading to deep stillness where one forgets both internal and external existence, merging body-mind with the Taiji (Supreme Ultimate).

On "forming the embryo" (elixir crystallization) and "shedding the embryo" (spirit liberation):

During initial elixir formation, guard the "life stem" (Dantian) like a fetus depends on its umbilical cord. After the ten-month (alchemical gestation) cycle completes, the primordial spirit ascends to the Niwan Palace (upper Dantian), ultimately capable of shattering emptiness and traversing all directions. As the verse says: "At accomplishment's peak, luminous pearls appear in all directions like night-brightening jewels."

Final summary:

These eighty lines contain the core secrets of the Golden Elixir path. During practice, bodily responses manifest as wondrously as valley echoes, sunlight focused through burning mirrors, or water gathered with moonlit dew collectors (ancient metaphors for natural resonance)—all depending on the vital communication between breath and the cosmic correspondence of Heaven and human.

This commentary on Cui Gong's Mirror for Entering the Medicine elucidates the essential cultivation techniques for the five key watches (wugeng) in Daoist Neidan (internal alchemy) practice:

First Watch (7-9 PM):

Sit upright in meditation, regulating the primordial Qi (Yuanqi). Enter a state of undifferentiated thoughtlessness while maintaining true intention (zhenyi), with breathing long, fine, and gentle. At this stage, a millet-sized "dan embryo" forms within, containing the transformative power of heaven and earth.

Second Watch (9-11 PM):

Maintain a purified mind in empty tranquility. Through inward contemplation (huiguang), perceive the mystery of "being born from non-being." Disperse distracting thoughts (qunmo) with the unwavering determination of a golden lion's roar. When the practice matures, one may suddenly attain cosmic longevity.

Third Watch (11 PM-1 AM):

This period resembles the rooster heralding dawn or the first stirring of Yang energy at winter solstice. Through the method of "drawing from Kan to replenish Li" (extracting kidney-water to nourish heart-fire), elevate energy to the Niwan Palace (crown point). Circulate the celestial cycle's firing process, facilitating the fusion of "lead" (kidney Jing/essence) and "mercury" (heart Shen/spirit). After nine cyclical refinements, visions of swirling snowflakes appear, heralding imminent transcendence.

Fourth Watch (1-3 AM):

Enter the realm of peaceful bliss where all thoughts dissolve. The mouth fills with nourishing saliva (Huachi water), nurturing the spiritual root. In deep stillness, one hears celestial music resounding, attaining the state where "the Dao is empty yet inexhaustible," securing one's name on the register of immortals.

Fifth Watch (3-5 AM):

As the moon sets and dawn approaches the east, the true self (Yuanshen) manifests within. Jade phoenixes draw chariots at the Jade Portal (lower Dantian), while golden dragons coil around the Golden Summit (upper Dantian). Ultimately shattering the void's constraints, the practitioner radiates golden light in all directions.

Note: Terms like "lead-mercury" and "Kan-Li" are Neidan metaphors representing vital substances—essence, spirit, kidney-water, and heart-fire respectively. The entire process refines Jing, Qi, and Shen through breath and mental discipline, culminating in spiritual and physical transcendence.