《道樞》Vol. 29

The Upper Clarity Chapter on Gold and Jade

(The essence of the Five Qi is refined; firmness and yielding each find their proper place, and one roams among azure clouds.)

Yanluozi said: Gold is foremost among the Five Phases, the root of the five destinies, and the source of the Five Qi. When firmness and yielding each find their proper place, those who can ingest this gold may roam among azure clouds and in the abodes of immortals. For this reason it is called “Gold and Jade.”

Someone asked, “Where lies the essential method?” The answer was: Take five liang of the Sun (lead) and fifteen liang of the Moon (mercury). Combine them and grind them finely in a mortar. Grind them until they are extremely fine, wrap them in paper free of ash, and place them in a long iron vessel. Press them down firmly, cover them completely with Tang ash, and pack it tight so the vessel is filled. Then seal the mouth of the vessel with salt and clay, and heat it until dry. Bury the vessel mouth-down in a pit, leaving exposed only the place where the medicine is held. Burn five jin of charcoal continuously until one period of fu has passed. When it is taken out, the medicine will have been fired without scattering. This is called the “Black Pearl”: black with a jade-green sheen, moist and lustrous. This is the first transformation. This stage is like “the flying dragon subduing the tiger” and often takes three years to complete; it is also like “nurturing the crane and concealing the tortoise,” and may sometimes take dozens of autumns.

Next, place this elixir in a bottle and cover its mouth with a shaved brick. Seal it all around with clay to a thickness of half an inch and leave it to dry in the sun. Build an earthen enclosure one chi and nine cun high, three chi wide, and three cun deep. Lay a nine-cun-thick bed of cattle and horse dung inside, place the elixir in it, and cover it with enough dung to make ten dan in all. Then apply the fire. Once the fire has gone out, break the bottle and take out the medicine. It will be reddish yellow, like pieces of dried bean paste. This is called the “Yellow Sprout,” also known as the “Golden Puppy” or the “Sun’s Dripping Pearl.” A scripture says, “The Sun’s Dripping Pearl enters the Flower Pool”; the mercury referred to is this substance. The saying that mercury nurtures purple gold, called the “Purple River Chariot,” describes this stage. This is the second transformation.

Next, place the medicine in a bottle of the kind used for an offering cart, one that has never held oil. Cover its mouth with a shaved brick and seal it all around with Six-One clay to a thickness of four fen, leaving no gaps. Let it dry in the sun, set it on a brick, and fire it with five jin of intense heat for three periods of fu. When the time is right…

Note for understanding the passage: This chapter describes Daoist Waidan (external alchemy), or the refining of the Golden Elixir, and uses coded language. “Sun” usually refers to lead, and “Moon” to mercury. “One fu” and “three fu” indicate periods of firing or stages of heat. “Azure clouds” and “the abodes of immortals” evoke the realm of immortals. “The flying dragon subduing the tiger” and “nurturing the crane and concealing the tortoise” suggest prolonged gentle nurturing and caution against rushing. The materials and procedures described involve heavy metals; today they are generally treated as historical texts and should not be followed.

A Plain-language Interpretation of The Pivot of the Dao

The Third Transmutation: Purple Spirit Elixir

When the firing has reached its proper stage, extinguish the furnace and break open the elixir vessel to take out the medicine. Its color is a lustrous purple, and it weighs as much as gold. This is the Purple Spirit Elixir. Taken for forty-nine days—seven times seven—or sixty-three days—seven times nine—it can cause the bones to become like gold. This is the third transmutation.

The Fourth Transmutation: Dragon-Tiger Elixir

Choose another elixir vessel, this one bright white in color, and prepare it as before. Place it in an Eight-Trigram furnace—an eight-sided furnace one chi and two cun wide and equally high. Insert a sword at each of the eight sides, with a mirror hanging from each sword’s tip. Set out a cup of water and an incense burner at each side, then kindle the fire and begin the refining.

When the fire has gone out, break the vessel and take out the elixir. It is blue-green in color, rings with the crisp sound of golden wind, and weighs twice as much as gold. This is the Dragon-Tiger Elixir. At this point the method has reached its full accomplishment. Why is it called “Dragon-Tiger”? When horse teeth—the name of a mineral—are combined with sulfur, and the Celestial Talisman advances and retreats, the spirit and Qi are drawn from the lunar palace in the Palace of Li, producing a radiant glow like rosy clouds. This is the fourth transmutation.

The Fifth Transmutation: Golden Tiger Elixir

Place the elixir in a fire-jade vessel, a kind of porcelain produced in Dingzhou. Use a furnace of harmonious Yang to blow on it for five thousand breaths, adding charcoal gradually. The charcoal must not touch ash or earth, and the fire at the bottom of the furnace must not go cold. If it does, Yin energy will enter from outside and the elixir vessel will crack. Add the charcoal slowly, then continue blowing on the fire for eight thousand breaths. When the fire has gone out, take out the elixir. Purple clouds lie over it, while golden stars and jade pillars appear below; five-colored lights shine and mingle. This is the Golden Tiger Elixir. This is the fifth transmutation.

The Sixth Transmutation: Medicine for Preserving Life and Long Life

First combine the Dragon-Tiger Elixir with eight liang of Maiden—a term for lead or a lead compound—and grind the mixture ten thousand times to refine it into the Golden Tiger Elixir. Then calcine it in fire weighing seventy-two jin. This produces the medicine for preserving life and attaining long life. This is the sixth transmutation.

The Seventh Transmutation: Flower-Nai Elixir

Take the elixir for preserving life and combine it with one jin and twelve liang of mercury. Grind the mixture one hundred thousand times. The power of the divine elixir can transform mercury. After drinking half of it, place the rest in the Heaven-and-Earth furnace, a vessel made of a silver alloy, and let it warm and mature for ten days. This produces the Flower-Nai Elixir. At this point, the scene within the furnace is like this: a golden dragon twists and turns amid purple Qi; a purple phoenix soars above the furnace; a vermilion crane nests in the pine branches; and a green tiger lies in the right-hand chamber. This is the seventh transmutation.

The Eighth Transmutation: Yin Elixir (Bone-Releasing Numinous Sand)

Put the elixir in a porcelain bottle. Add two jin of Han River arsenolite, a mineral, and pound it together with sour wine, meaning rice vinegar, to make a paste. Coat the porcelain bottle thickly with the paste. Carve a niche into the north wall and set the bottle inside, then seal the opening with more arsenolite paste. Leave it undisturbed for one hundred days before taking it out. This is the Yin Elixir, also called Bone-Releasing Numinous Sand. This is the seventh transmutation, as indicated by the text’s phrase “this is its seventh transmutation.”

Note: This passage comes from Daoist Waidan (external alchemy) literature. It describes the furnaces, implements, and elixir names used in the third through seventh—or perhaps eighth—transmutations of the “Ninefold Transmuted Return Elixir.” Terms such as “horse teeth,” “Maiden,” and “lunar palace in the Palace of Li” are alchemical codenames. Historical accounts of the specific ingredients and procedures vary; the passage is explained here only in its literal sense and is not practical guidance for carrying out the procedures.

On the Elixir’s Passing from Death to Life, the Eighth Transformation. Store it in a bottle and, on the Clear and Bright day, sink it in a well. After one hundred days it can be taken: those who take it may live forever; after two hundred days they become earthly immortals; after five hundred days they ascend to heaven in broad daylight; and after a thousand days their whole household rises and flies upward. This is the White Emperor’s Jade Frost and the Purple Sovereign’s Red Snow: the Maiden laughs in the furnace, and the Infant rejoices in the cauldron—the Ninth Transformation. The formula says: My eyes are like the sun, my ears like the moon, my nose like a gate, my heart like the sea, my intention like the wind, and my body like the earth. The Five Directions and Five Sacred Mountains all return to me; every living being on earth is my child.

The Golden Tiger, Lead, and Mercury

All things flourish as the essence of Heaven and Earth; they form through Yang and are born through Yin.

The Primordial Sovereign said: “The Golden Tiger, lead, and mercury are all contained within the Five Phases (Wood, Fire, Earth, Metal, and Water). All things form through Yang and are born through Yin. Yin is the foundation of the Dao (the Way), while Yang is the beginning of the One. Yin and Yang contend with and transform one another, and patterns and forms are established. Thus Kan is one and Li is two: this is a return from Yin to Yang. Two Fire and one Water: this is a return from Yang to Yin. Water two, Fire one: the former is the image, the latter the substance.

“The images of the Five Phases are also complete within the human body. The heart is Fire, hidden beneath the lungs, and its number is one. The kidneys are Water, paired and located at the Gate of Destiny, and their number is two. We can see, then, that Fire one and Water two are the ancestors of the Dao. Through internal cultivation, attaining the One produces the Yin Elixir; through external cultivation, attaining the One produces the Yang Elixir. The joining of the Returned Elixir never goes beyond the Five Phases; the key lies in recognizing the true nature of lead and mercury.

“Accordingly, the images of the Great Changes (Da Yi) were used to establish 384 zhu, together with the twenty-four seasonal periods. The two arcs of the sun and moon face one another above and below, making two times eight, or sixteen. Sixteen liang are also established, with Kan and Li as the ingredients, Heaven and Earth as the furnace, and Qian, Kun, Zhen, and Xun directing the cycles. White-horse sprout-cinnabar is Yin energy; gold cinnabar is Yang energy. The life and death of all things return to Earth. Earth governs yellow, and Metal governs white. Consider a chicken egg: yellow within and white without, formed when the two energies interact.

“In the north is the black Water of Zi, where Metal resides. It is the beginning of the Five Phases and the foundation of the Dao. Within it, cinnabar of Jia and Yi naturally sprouts, illuminated by the sun and moon.”

A Plain-Language Interpretation of The Pivot of the Dao (Dao Shu)

Lead is born within cinnabar ore. Its nature is white, and it lies hidden beneath fire. This is what is meant by “Heaven-born lead.” (Chen, one of the Earthly Branches, here symbolizes a direction and season.)

The area around Jinxi belongs to the south, corresponding to the color red and the position of Wu. Wu is where fire resides. Cinnabar is the parent of mercury. The east belongs to the blue-green Wood phase and corresponds to the position of Mao. Wood is the root of Yin and Yang. All things receive one Qi (vital energy) and are born from it. The essence of Jia and the soul of the sun are the parents of fire.

The west belongs to white Metal and corresponds to the position of You, where water resides; it is also the moon’s corporeal soul. Turning from north to west, Mao and You face one another at a distance. Metal overcomes Wood, and water and fire revolve in their cycles; from this, the essence of the “Great Return” is refined. The center belongs to Earth and is yellow. Wu and Ji reside in the “Flowery Pool.” Yellow can restrain water so that it does not flow, bringing it back to stillness. Thus Earth is the parent of returning the elixir: parents are those able to subdue all things. Therefore the Metal cauldron corresponds with Earth, and the Three-Five and One accord without the slightest deviation.

The sun and moon are essences of Yang, and their number is nine, with another nine within it. Their color is black, an image of Ren and Gui water in the north. This is called “Yin essence within Yang”: Yang contains Yin. Thus the fire of Bing and Ding in the Palace of Li receives the name “Nine.” Its Qi congeals into Vermilion Blossoms; refining them gives them firm form. This is the principle of the Three-Five and One. For this reason, the immortals of old refined the sun’s essence, returning the body to pure Yang.

Mercury belongs to the category of water. Its nature contains Yang within and displays Yin without: Yang is symbolized by yellow, Yin by white. We can therefore see that what is red outside and yellow within is mercury born from cinnabar; mercury is born from lead. This is Yang containing Yin: Yin is not alone, nor is Yang without its counterpart. The moon forms from accumulated Yin essence and resides in the position of Kan. Its number holds to One; Yin and Yang contain the mysterious, and the soul and corporeal soul correspond. The toad and rabbit in the moon symbolize Yin and Yang. Their color is white, an image of Geng and Xin Metal in the west, and they are called “Yang within Yin”: Yin contains Yang. Does this mean that Ren and Gui water in the Palace of Kan obtains One? The moon’s Metal nature is Yang, Yin on the outside and Yang within: Yin is symbolized by white, Yang by yellow. We can therefore see that what is white outside and yellow within is white Metal born from the River Chariot. The river is water, the chariot is fire, and red is cinnabar. Hence it is said that cinnabar is produced from Metal: this is Yang within Yin, not standing alone.

Cinnabar and lead are placed in the furnace and melted down through refining.

Plain-Language Interpretation of The Pivot of the Dao

Replenishing essence and Qi into the “Elixir Soul” is called the Chanu (the Yin, receptive element that can be refined in inner cultivation). Bringing “sand” into conjunction with the Chanu means joining lead to it. Here, lead refers to Yin essence or true lead, not an ordinary block of lead bought in a shop. Sand refers to white metal, a metaphor in alchemy for refined gold or white Qi, not silver jewelry sold in the marketplace. The formula says: first, the foundation of the Elixir lies in water, and lead is contained within it; second, the foundation of fire lies in wood, and the tally—meaning the timing of the fire and the signs that confirm it—is contained within it; third, the foundation of earth is the mother, and metal is contained within it. So when cultivating the Returning Elixir, which gathers scattered Qi back together and forms the inner Elixir, how can its foundation be established without mastering the timing of the tally and the fire?

The five alum compounds, eight minerals, and similar substances commonly spoken of in the world are all inert and dull; they are not ingredients for the Great Elixir, the true Golden Elixir of inner cultivation. The Great Elixir uses none of the external substances such as gold, silver, copper, iron, lead, mercury, tin, copper sulfate, orpiment, realgar, sulfur, arsenic, cinnabar, mercury, soot from a pot, dew, frost from mulberry leaves, or human urine. Sand that has been treated with fire may perhaps cure illness, but taking too much will shorten one’s life.

Mercury—that is, quicksilver, a metaphor in inner cultivation for nimble, active essence and Qi—is the essence of water. When it rises and flies, it becomes a flowing pearl, also called flowing mercury. Zhen is the eldest son and succeeds to the father’s place; this is what flowing mercury signifies. Thus cinnabar is said to be the father of flowing mercury, and Wuji the mother of gold. If it condenses into white metal, it is the white substance that takes form from the One. Gold and water follow the same Dao and are used together, so gold is called black lead. Yang is born within Yin, restoring youth to old age. Why? When the Qi of lesser Yin reaches its extreme, it turns back. Thus mercury is born in the north, in the Kan position, and must then enter the position of fire and join with it before the Great Elixir can form. Those who do not understand this take ordinary lead, black tin, and mercury to be the River Cart, the route and vehicle by which essence and Qi circulate; they take realgar to be earth, and gold and silver to be the mother. None of these is the true source of the elixir’s ingredients.

Mercury may be found in lead, copper, or iron; it may be found in plants or in ores. What is called true lead is that which, in nature, has mother and child in the same hollow and is born as one body. The kind that contains silver has this meaning: lead is the root of the Great Elixir, and spirit water is the mother of gold; mother and child naturally come together in harmony. Gold is the essence of the Elixir and occupies the Yang position. Mercury joins with the Qi of Li fire, corresponds to a Yin line, and contains the numinous power of Heaven and Earth and the essence of the sun and moon. When decline reaches its extreme, renewal begins; when Yin is exhausted, Yang is born. Both follow the course of Heaven.

On the first day of the lunar month, the sun receives the tally. The six Qi transform from nature into feeling, and by the sixteenth through the thirtieth day they are spent; then the Qi again transforms from feeling into nature. From this the moon’s dark aspect is born, giving rise to its waxing and waning. Gold is the wife and wood the husband; Zhen is the eldest son and Dui the youngest daughter. White is gold, black is lead. The pairing of Yin and Yang and the joining of water and fire all belong to this principle of creation and transformation; they do not come from piling five metals and eight minerals haphazardly in a furnace.

People in the world are blinded by cleverness and intelligence, and in the end their nature and life are neglected. Though endowed with a gentle and yielding nature, they lose the good root of the Dao. The worthy sages of earlier generations took gentleness and yielding as their foundation, and so could harmonize Yin-Yang. In the lineage, they received the Yang Talisman—the laws governing the movement of Yang. By tracing it back to its source, they could understand the transformations of the Five Phases and the principles of cooking and refining. Even sages who heard it were deeply convinced, and so they entrusted the essential instructions to later generations.

The way of cultivation lies in following nature, keeping to its rules, observing what is subtle, and practicing until there is no selfishness or sense of self. It is also like using sand to warm and nourish lead, and using the Elixir to nourish life. When the Yang Talisman descends, Dragon and Tiger meet; when the Yin Talisman rises, their movement circulates freely. The secret of the Great Elixir is not found by grasping wildly at what is nearby, but in the proper sequence of nature, life, and the firing times.

As you breathe primordial Qi and maintain a body of emptiness and stillness, observe the movement of Qi through the Ren and Du vessels. As soon as it moves, it must circulate and connect. When Water and Fire are harmonized, the spirit chamber—the Dantian furnace and cauldron—lies below in the Kan position; only at the center does it occupy its proper place. During the pause in breathing, examine the primordial Qi of your own breath: the inner medicine must rise through the Three Passes and descend through the Three Yin regions. This is the correct method of the Seven Returns and Nine Revolutions. Draw pure Yang Qi from above and subdue Yin Fire below; only when Water and Fire are harmonized can the Five Phases be brought into balance.

Within the kidneys, at the very hour of Zi, the authentic Qi begins to move. When prenatal Qi joins with the postnatal waters of the spine, they transform into an embryo. Once this is attained, Kan and Li unite, and Dragon and Tiger lie dormant and still. The Yang lines rise, the Yin lines descend, and all Five Phases return to “One,” reverting to the Limitless. The formless, clear Yang Qi steams upward and fills the six bowels; formless Yin Fire blazes and warms the nine chambers within the body.

In the spirit chamber, bright clouds like a dragon rise to reach the Celestial Palace, while emerald mist like a tiger descends to meet the Underworld. Kan and Li meet, moving up and down in turn as their influences rise and fall. When the Yin Talisman rises, the work of transformation begins; when the Yang Talisman descends, the true nature is preserved. As Kan and Li join, the work by which Heaven and Earth nurture life becomes manifest. This is the military formula for the harmonizing of Water and Fire and the contest between Dragon and Tiger.

As the Yin Talisman rises and the Yang Talisman descends, Kan and Li meet and the pathways of the three upper and three lower channels come together. Knowing the subtle moment—the crucial point in the firing times—and maintaining attentive listening to the breath are the essentials of cultivation. Above all, keep to the attentive listening of Wuwei. If the Yang Talisman does not descend and the Yin Talisman does not rise, circulation stops. If Yin and Yang no longer sustain the body’s nourishing and defensive Qi, a person will waste away and perish. Practitioners must observe their life talismans, the workings of Heaven, and the channels of Qi, bringing heart and eyes into accord and maintaining the pure, still body of the Dao. In daily life, remain balanced and self respecting; do not let the habits of external things contaminate you, and do not let human attachments bind you and disperse your original nature. The family talisman within Yin is like the mother, and the child talisman within Yang is like the child. The mother dwells in the central spirit chamber, and the Five Phases return to unity within the body. This is the general formula for dual cultivation of nature and life, and for the Golden Elixir of Dragon and Tiger, lead and mercury.

Pure Yang Qi moves for thirty-two days, its power drawn at Mao and You; the Five Phases contend, and another sixteen days are gained. Heaven and Earth move back and forth like a dove pecking: Yin Fire rises and Yang descends, their influences passing to and fro. This is also like the clash between Mao and You, when the Five Phases overcome one another. Lead and mercury meet; Dragon and Tiger are subdued. After two circuits of the Water and Fire cycle, a precious Elixir forms in the cauldron. One cycle of the harmonizing of Kan and Li can refine the Nine Revolutions Golden Elixir. Kan and Li join for several days: this coincides with the bathing of the Twenty-Eight Lunar Mansions and the sixty hours of half a sexagenary cycle. Yin and Yang infuse one another, Kan and Li unite, and the original spirit is perfected. Once Kan and Li separate, lead and mercury each return to their proper place. From then on, the Elixir completes its nine revolutions, and in an instant one can refine what is needed for use. This is the general formula for the union of Qian and Kun and the Golden Elixir of Dragon and Tiger, lead and mercury.

The firing times for the Seven Returns and Nine Revolutions are, in outline: Kan Water, Li Fire, Zhen Thunder… (the original text continues by explaining the sequence of firing times according to the trigrams and the cycle of the heavens.)

This passage explains how Yin-Yang, lead and mercury, the Five Phases, and the Eight Trigrams work together in Neidan cultivation. Its general meaning is set out below.

The Yin Soul and the Kan Position

The Yin soul resides within the Kan trigram, and its “medicine” arises in a hidden, dark place.

What Is the Metal Lord?

The “Metal Lord” is metal as symbolized by the Star of Great White Venus. Metal is ranked highest among the Five Phases, so in alchemical practice it is also called lead. When metal enters the palace, the fire of Taiyi and the city of the Geng position are present; the red bird keeps watch, while the yellow bird, Azure Dragon, White Tiger, and other beings gather. This is what is meant by “joining in accordance” (cantong): Yin-Yang and the Five Phases are matched and brought together in one crucible.

Lead and Mercury as Husband and Wife

Black lead enters the moon and is paired as husband and wife; the Yang soul and Yin soul naturally unite. People do not know that the five metals and eight minerals are originally the total number of Yin and Yang. Through their matching and circulation, they form the Elixir. The eight minerals correspond to the Eight Trigrams (Bagua), and the five metals correspond to the Five Phases (Wood, Fire, Earth, Metal, Water).

Wood, Fire, Metal, and Water

“Wood that does not turn to ash” is the essence of Jia Wood, which is controlled by metal. Water is conceived within metal, and water must always be present with metal. Fire is conceived within wood, and wood must be used to control fire.

Lead water is a liquid that arises spontaneously within cinnabar and governs Yang; mercury water is a liquid extracted from cinnabar and governs Yin. Fire serves as the talismanic marker; mercury fire is water and fire joined in one form. When the two substances are in the cauldron, the Direct Talisman controls them so they cannot fly away. Killing force then descends upon the cauldron, consuming and transforming them; this is why the process is called the Great Return (returning the Elixir).

What the Classics Say

The Primordial Lady says: “Cinnabar and water essence unite through metal; their measures join without imbalance, becoming supremely sacred and supremely potent.”

The Great Mystery Yin Talisman says: “The Dao gives birth to Yin; Yin gives birth to Yang; Yang gives birth to the Five Phases. The Five Phases combine to form the returning Elixir, hence the names Dragon and Tiger. The Dragon is Yang Qi, and the Tiger is Yin Qi—that is, the positions of metal and wood. Yang begins in Zhen (one Wood), and Yin begins in Xun (two Wood). When the moon receives the talisman from the two Wood positions, it gradually wanes. If mercury has not yet been subdued, it cannot become the Great Elixir; it must be nurtured and kept in its place.”

Three Years and Subduing Mercury

“In the course of three years” often refers in alchemical practice to three months. Nurturing the fire for one month can take the rightful Qi of a year. When its color becomes pale blue and luminous, release its toxins in a cold spring. After one month, remove it and steam-refine it; this is one period of subduing. Refine it with paper mulberry juice. After fasting in purity for fourteen days, face east, close the eyes, and click the teeth thirty-six times before taking it. This can dispel illness and restore youth. If it is kept for five years, consuming three zhu can bring long life; if kept for nine years, consuming two zhu can enable ascent. The Primordial Lady also says: “I possess a celestial talisman with which, using fire, I make a golden cauldron.”

The original is written in coded language that draws on both Daoist Neidan and Waidan. Lead and mercury, Dragon and Tiger, the Eight Trigrams, subduing mercury, and the Great Return each have established referents. This plain-language explanation clarifies the meaning without replacing practical instruction transmitted by a teacher.

The Dao Pivot: A Plain-Language Interpretation

The key lies in “Jia”: Jia is the root of Wood and Fire, and its number is three. Its completed number is eight. Its proper position of birth is in the East, while it resides in the positions of Bing and Ding. It is the teacher of all things and the parents of Fire, as well as the sun’s vital essence and spirit. When Yang Qi first stirs, it shines forth and gives form; this is called the Sun’s Soul. In the sky, the sun is the Direct Talisman, able to bring forth and nurture all things; on earth, it is the Direct Function, able to cook and ripen all things. Because Yang Qi divides and takes distinct form, it is called the “Blue-Waisted Messenger, Essence of Wood.” This expresses the principle by which Yin and Yang, as two natures, join in accord and confirm one another through their participation.

Golden Sand: Fire and Wood unite, returning together through “Three, Five, and One,” and possess an inherent numinous nature. When the three—Wood, Yang essence, and radiance—join and take form, they are forcibly named Golden Sand: the essence of Heaven and Earth.

Elixir: It belongs to Yin within Yang. Mercury is Yang, yet in this arrangement it becomes the minister, the second. Cinnabar is this Fire.

Lead: With the Five Earths as its mother, it belongs to Yang within Yin. Mercury is Yin, yet in this arrangement it becomes the ruler, the first. Black Lead is the foundation of Water. The Yang Soul, refined nine times, is true Water, an image of dwelling in the Li position, Yin within Yang. The Yin Corporeal Soul, refined three times, is Yellow Silver, an image of dwelling in the Kan position, Yang within Yin. It is called Quicksilver. When the Fire positions intersect, primordial chaos joins of its own accord; overcoming and restoring, they return to unity and take form with nothing beyond them. Thus it is said that Yin Fire naturally joins with its tally. Its principle is like the waxing and waning of human life, and so accords with the Way of Heaven.

The Primordial Lord said: “The highest-grade Golden Elixir uses the mother to overcome the child, and the child then vanishes of itself. In the advance and retreat of Yin and Yang, the numbers are seven and eight. Receiving Qi, they separate; after fifteen days, they reach the end of a cycle of thirty days. Then, through returning and nurturing, they become open to the numinous. In the ninth month, the two Mercuries of Yin and Yang share one form. First, they must be joined in accordance with nature. When the Direct Talisman’s movement follows the lines and images of the hexagram, the Elixir will become numinous.”

The Primordial Lord said: “Heaven and Earth return and reverse; the movement of the Three Ones accords with the Heavenly Tally, and there is also a formula for modeling their forms. As for the movement of the tally: when, in the month of Zi, the Yang line has stirred, it is as though life is born in the Kan position. ‘At the beginning, nine: The hidden dragon. Do not act.’ Yang Qi is still undivided, in primordial chaos. After the winter solstice, a single Yang rises forcefully in Jiazi, taking the lead. The Upper Origin begins at the hour of Zi. When the second Yang is born, ‘The dragon appears in the field.’ The line stirs at the Awakening of Insects; Yang is received and takes charge. This is called the birth of a single Yang. When it encounters Jia, it meets its parents. Thus, in the eleventh month, Yang is received.”

This passage from Daoshu explains how, in refining or cultivating the Elixir, practitioners “advance the tallies” according to the hours, solar terms, and line images, regulate the fire, and match weights and measures. In this way, the workings of Yin and Yang in Heaven and Earth are reproduced in the fire within the cauldron.

Beginning at the zi hour: Yang within Yin

The tally procedure and its operations begin from zi (the zi hour, the start of the day). The birth of the first Yang occurs deep within darkness, corresponding to the positions of ren and gui (Water, the north, and the image of the Kan trigram). The tally is used in the month of jianwu (the wu month, in summer). Although Yang is then at its height, signs of Yin’s birth are already present within it; the method of using the tally follows the same principles as the Yang season and its governing rules.

The classic says: in beginning the count and advancing the tally, zi serves as a metaphor for weights and measures—the quantities of the ingredients or the fire. When a line moves, fire is concealed within the initial Yin: this is Yang fire, with Yin attached to Yang. One cycle of tallying amounts to roughly four hundred and five zhu, which is then matched to the liang. Zhu and liang were ancient units of weight; here they suggest the precise coordination of the fire and the quantities of the ingredients.

The sun, moon, Five Phases, and the spring equinox

The mysterious images of the sun and moon’s movement and the waxing and waning of the Five Phases begin with the number of the first Yang’s birth. This symbolizes Heaven and Earth beginning to act and to reach through to the nature of the myriad things. At Jingzhe, when living things begin to stir, the tally and the fire schedule proceed in step with them. The classic also says to use the tally at the spring equinox, when day and night are equal. The Yang lines gradually increase until Dazhuang (one of the twelve waxing and waning hexagrams, signifying the flourishing of Yang). From the morning of the new moon to the fifth day in the middle of the ten-day period, the image is of Fire and Wood governing the transition between spring and summer; the fire shifts from “civil” (gentle and nurturing) to “martial” (fierce and refining).

The autumn equinox, growing Yin, and the dark and new moon

On the sixteenth day of the ten-day period, the autumn equinox, when day and night are equal, is taken as the measure. The Yin lines gradually increase until the month when Yin is at its height, symbolizing Metal and Water governing autumn and winter. The fire shifts back from “martial” to “civil,” and the hundred ke—the time divisions of a day and night—are also changed. This corresponds to the mysterious image of things concealed in Heaven and disappearing at hui, the end of the lunar month. It is the numerical correspondence of tiao and nu, the moon’s phases at the beginning and end of the month.

Why the count begins at zi: weights and measures, and the water clock

The tally begins at zi, but this does not mean that zi is the parent of “fire.” Zi marks the starting point of a line within Yin and serves as a metaphor for weights and measures; it is the total number at the pivot of Creation. The waxing and waning of Yin and Yang and the advance of the tally must accord with the water clock; the division of Qi must accord with weights and measures. The tally begins to move at chen and si. After two and a half cycles, one sequence is complete; the division of Qi ends at xu and hai, which are no longer the central positions of zi. At the winter and summer solstices, Yin and Yang exchange their positions above and below. Therefore, the tally must be used to tend the cauldron carefully, strictly advancing and retreating the weights and measures in accordance with the line images. At the same time, Yin is joined to zi. The charcoal is laid over the vessel to retain warmth and seal in the Qi; it faces away from Yang and toward Yin, with the contents hidden as tightly as a beehive, so that no Qi can escape.

The classic says: from one point to the seventh and a half marks a season; each time zi arrives, the count is increased. Zi arises in the position of Kan, so Kan represents “one Yang within Yin.” Starting from zi, the lines are gradually added until Lixia and the summer solstice, symbolizing the height of the fire. The fifteen or sixteen days that run counter to the “martial” phase bring the tally’s total to sixty. Before the full moon, the phase is Yang; after it, Yin. Yin begins to grow from the seventeenth day and continues through the fourteenth, gradually receding until the winter solstice—the point at which the Five Phases’ count is exhausted and the cycle concludes at thirty.

Reading note (not part of the classic): The passage weaves zi, wu, the spring and autumn equinoxes, Jingzhe, the two solstices, the new and full moons, line images, weights and measures, zhu and liang, and the water clock into a single schedule for regulating the fire. This is a characteristic Neidan method of modeling the workings of Heaven and Earth. The specific steps for advancing the tally should be considered alongside the full discussion of the cauldron method and ingredients, and should not be put into practice on the basis of isolated lines.

This passage describes the daily rules for combining talismans in Daoist practice—that is, matching talismanic methods with the timing of Heaven and the positions of the hexagram lines—by aligning the upper and lower positions, formation, and beginning and end of the six lines with the Five Phases (Wood, Fire, Earth, Metal, and Water).

First period: Two and a half days make one Qi, or thirty double-hours. After another two and a half cycles, the five Qi divide and return, passing through the twelve earthly branches (the twelve double-hours). Five cycles in all make sixty double-hours. When rotating and applying the talismanic method, five days make one period, for which the fifth line is used.

Second period: This is again two and a half days, one jin, or thirty double-hours. After two and a half cycles, the five Qi divide and return; five cycles make sixty double-hours. The talismanic method proceeds through fifteen days, completing three periods in all and using fifteen lines and thirty talismans.

The scripture says: the first five days of the ten-day period are Yang talismans, when Fire and Wood govern; the latter five days are Yin talismans, when Metal and Wood govern (“Metal and Wood” follows the original text). At the initial movement of the lines, Yang is odd and Yin is even, corresponding to sixty-four zhu; ten liang use two talismans. The first line is fixed. When it meets Zi, add; when it meets Yin, retreat. The cycle begins again, modeled on the celestial talisman.

To begin the outflow at Jianzi—with the Zi hour or Zi month as the starting point—is to mark the beginning of Yang movement. Chaos is about to divide, but “the hidden dragon has not yet appeared” (an image from the Classic of Changes, in which the dragon remains concealed). Jia must therefore serve as the father and mother of Yang Qi, dividing the Qi and assigning it to the Yang Way.

At the beginning of the Upper Origin, Yang begins to move. In applying the talismanic method, Zhen and Fu govern; their image is like the initial nine, and they mark the Qi in early spring. In early spring, on the first day, the first line begins at Zi; on the second day, the second line; and so on through the fifth line on the fifth day. Each time the talismanic method is applied, it passes through the twelve double-hours. After two and a half cycles it reaches Si, making thirty double-hours, or two and a half days. From Wu, the Qi divides and proceeds through another two and a half cycles, ending at Hai after sixty double-hours, in correspondence with mid-spring. Mid-spring belongs to Yang. The five lines of the Upper Origin make ten talismans: on the sixth day, the sixth line begins at Zi; on the seventh day, the seventh line; on the eighth day, the eighth line. On the ninth day, the second nine follows the method of Kun and Dui, as their Qi intermingles, in correspondence with late spring. Late spring reaches Si after thirty double-hours, marking the third nine. On the ninth day, the ninth line begins at Zi; on the tenth day, the tenth line begins at Zi and ends at Hai after sixty double-hours. This is the period governed by the Upper Origin. When the Qi divides, count the lines and receive the talisman: from Zi through Wu and Hai, return and begin the three periods again.

Early summer is a Yang retreat. The Middle Origin has forty lines and two hundred talismans—the third period begins on the eleventh day… (The detailed method for each “period” continues below and should be read in sequence with the complete text.)

Brief background note: Texts of this kind often set out calendars linking celestial timing, hexagram lines, and the Five Phases in Neidan, the regulation of the firing times, or talismanic methods. They align “periods,” “double-hours,” “lines,” and “talismans” with days, five-day spans, ten-day periods, hexagram lines, and solar terms, so that cultivation or talismanic practice follows the movement of Heaven and Earth. “Upper Origin” and “Middle Origin,” along with terms such as “early spring” and “mid-spring,” divide the seasonal year into practical sequences for applying talismans.

This scripture describes the application of the "Yao-Chen Method" (a cultivation technique combining the hexagrams of the Yijing with temporal cycles) in Daoist practice. The annual cycle is divided into six phases (known as "Six Hou"), each corresponding to distinct patterns of Yin-Yang transformation.

Beginning in midsummer (the second month of summer), Yang energy reaches its peak at noon (11 AM–1 PM), while Yin energy arises during the hour of Hai (9–11 PM). Practitioners must complete fifteen hexagram changes within fifteen days, with each hexagram corresponding to two and a half days—totaling thirty traditional two-hour periods (ancient days were divided into twelve Chen). This marks the phase of "Yang retreating to the lower origin" (a period of Yang energy turning inward), where the Metal and Water phases resonate, and the sun and moon shine in opposition.

By late summer (the final month of summer), Yang energy reaches its zenith and begins shifting toward Yin. The movement of heaven and earth resembles the turning of an axle. At this stage, cultivation follows the cyclical principle of "beginning with gentleness (Wen), transitioning to strength (Wu)." The process starts at midnight (11 PM–1 AM) and passes through the Chen (7–9 AM) and Si (9–11 AM) periods.

Autumn is divided into three phases: early autumn (the fourth Hou) initiates a sixty-six-day cycle starting from the fifteenth hexagram; mid-autumn enters the "Yin ascending to the upper origin" phase (Yin energy rising), employing twenty-two talismans (Fulu); late autumn reaches the sixty-third hexagram, shifting cultivation focus to the hours between noon (11 AM–1 PM) and Hai (9–11 PM).

Winter likewise consists of three phases: early winter is the "Yin centered in the middle origin" phase (Yin energy stabilizing), using twelve talismans; midwinter begins with the sixth hexagram; deep winter transitions into "Yin descending to the lower origin," completing the first two hexagrams in the final two days. The entire cycle embodies the natural rhythm of waxing and waning Yin-Yang, eternally recurring in perpetual motion.

This passage explains how “fire timing” and “tally signals” in Neidan (internal alchemy) cultivation are coordinated with the Dao. The language is dense, so the ideas are rendered here in plain English.

One line and the “two tallies”

“To accord with the two tallies of the initial rising and falling” means to match the two sets of tallies in the first cycle of “rising” and “falling.” Here, a tally is a system of markers for adjusting the fire’s intensity according to the trigrams and the hours, not a talisman drawn on paper.

“The two tallies and one line: the Kun body conceals Yang” means that these two sets of tallies correspond to one line. The image of the Kun trigram is a Yin body with Yang energy concealed within it, like the underlying condition of the eleventh lunar month or the Zi hour.

From one to fifteen and the Qian body

Counting from one to fifteen marks the stage at which De (Virtue/Power) becomes complete in the Qian body. Spring and summer tend toward the Qi of Fire and Wood; autumn and winter tend toward the Qi of Metal and Water. “Seven and eight come first; nine and six come after” describes the sequence in which trigram Qi and line positions are arranged.

Rising and falling, bending and extending, and the dark and new moons

Rising and falling, bending and extending, cycle between the dark and new moons, symbolizing the meeting of the sun and moon and the turning of the four seasons. “The hun returns and the po returns; the medicine is complete” means that spirit, Qi, hun, and po each return to their proper places, allowing the elixir—the refined essence of internal cultivation—to congeal.

Metal, Water, and nature

Within the nature of things, the Qi of Metal turns back to accord with nature. Therefore, Yin Fire and Yang Fire are established to bring Metal and Water together, but the measure must not exceed “one jin.” In alchemical formulas, this weight is a metaphor for the proper measure of fire timing, not an instruction to weigh out one jin. In this way, one accords with the Dao of Heaven.

The scripture also says that Yang uses odd numbers and Yin uses even numbers: “one ruler, two ministers.” When Yang Qi stirs in the first line, it corresponds to “two and eight.” Turning to the left, it becomes the “Yang tally,” and the fire gradually increases until it reaches the Great Strength hexagram. At the extreme of Yang, Yin is born. It then corresponds to “six and eight.” Turning to the right, it becomes the “Yin tally,” and gradually recedes to the first line of the Return hexagram. At the extreme of Yin, Yang is born again, and the cycle repeats.

The Qi of nine divisions and withdrawing and adding

When the Qi reaches the “initial nine” division, it belongs to the Yin way. If Yin begins in the upper cycle, the tally must recede. It gradually recedes until the “six periods” are complete, returning within three ten-day periods, when the numbers of the Five Phases have been exhausted. The key lies in “withdrawing and adding to the fire”: fire must be increased or decreased according to the mysterious images of the heavens and the trigrams, without losing the proper measure. Then the numinous spirit will naturally accord with them, and the Golden Elixir can be formed. Anyone who understands only one image or one set of techniques is no better than a piece of tile or gravel.

The Primordial Lord on lead and mercury

The Primordial Lord says: cultivating the Great Medicine requires true lead and true mercury. Metal and Water bring one another to completion, while Wu and Ji unite. Both Wu and Ji belong to Earth in the Five Phases and metaphorically refer to the spleen’s intention and thought joining with essence and Qi. This is like an embryo receiving Qi in the mother’s womb: the mother contains the child, and the child is concealed within Metal, naturally held and nurtured. The essence of Metal and the precious fluid oppose one another, one rising as the other sinks; Yang advances and Yin responds, like an egg with white on the outside and yellow within.

The River Chariot and the foundation of the elixir

The River Chariot—the circulation of essence and Qi along routes such as the Ren and Du channels—moves in an instant, “shedding the embryo” and returning to unity. This is the foundation of the elixir. The method is to use one trigram by day and another by night, using Qian and Kun in alternation. Xun and Zhen generate the twelve hexagrams, which shift between above and below as the tally signals are applied.

Thus, the “five cycles” are established and the “five Qi” divided. The cycle ends at Hai and begins at Zi; lines are added and withdrawn, advanced and concealed. The timing must accord with the Dao of Heaven and be measured by the water clock.

The water clock and controlling the fire

To make the water clock, take a large ceramic jar that holds one shi and drill a small hole in its bottom or side. Insert a slender bird feather, two or three inches long, into the hole and seal it with wax. Fill the jar with water and measure it with a sheng or dou to serve as the water clock. When the fire is used in accord with the tallies, there will be no error.

At the Zi hour in each of the twelve double hours, increase the measure—that is, increase the fire. After a full month, the images of the four seasons are complete. Maintain the practice for either nine months or three years, proceeding according to the method.

Brief glossary of terms used in the text

Tally / Yang tally / Yin tally: Rules for increasing or decreasing the elixir fire according to the trigrams and the hours, corresponding to leftward or rightward turning and the advancing or retreating of line positions.

Lead and mercury: Metaphors in Neidan, often referring to primordial essence and spirit, or to essence and Qi in relation to the mind. They do not mean the shop-bought metals.

Wu and Ji: The two Earth phases in the Five Phases. They often symbolize the central palace, the spleen’s intention, or the joining of thought with essence and Qi.

River Chariot: A metaphor for the ascent and descent of internal Qi through the channels, especially the Ren and Du.

Withdrawing and adding: An alchemical term for adjusting the intensity and timing of practice by increasing or decreasing the fire.

A Plain Language Reading of Daoshu

The Nine Cycles and the Joining of Lead and Mercury

When the nine cycles are complete, corresponding to the nine rounds of the Great Expansion’s number, the Elixir naturally becomes spiritually responsive. The scripture says: take the essence of “lead after three transformations,” then combine it with “two eights.” Halve that “two eights” to make the “seed beneath the earth,” which is also “two eights.” In this way, the essences and Qi will join of themselves.

When the two essences meet, the Yin and Yang energies stir one another. In an instant, they repeatedly transform and restrain each other. Gold and water then rise and float, blending into one; the essence of gold appears of itself and is called “yellow silver.” Gather it until its essence is exhausted, then add another “seed” according to the count, and it undergoes a further transformation. Once the gold is obtained, the two “strings,” mother and child, come to rest. What leaves the mother’s body is called “escaping the womb”; what enters the cauldron is called the “Fire Elixir.”

The Earthen Crucible and the Cauldron

The cauldron has an upper and a lower part: gold above and an earthen crucible below. This crucible is not a vessel used for casting metal in the ordinary world. The “earthen crucible” is the Earth Mother, made from a muddy pool in the region of the Luo and Fen rivers. (The clay is finely pounded and sifted, then mixed with a thin glue. Inside and out, it is shaped like an egg.) It is seven inches long and five inches around. At its center is the “spirit chamber,” three inches in diameter and two and a half inches deep. The whole vessel is egg-shaped, modeled on the primordial blending of Yin and Yang.

Without this earthen crucible, lead and mercury cannot be controlled; hence the saying, “Yellow can control water.” If the metal and earth of father and mother are used as the cauldron, the spirit can be raised.

The Day and Hour of Entering the Cauldron, and the Timing of the Talisman Fire

The day and hour for entering the cauldron must be chosen by matching the “four killers” and “punishments and clashes” with the Yang dates. The hundred divisions of day and night must also correspond to the hexagram lines: begin with Yin at the hour of Zi, and let the waxing and waning of the moon, the new and full moons, the changing weights, and the alternation of the civil and martial stages of the fire tally with one another. The cycle repeats and corresponds to spring and autumn. The talisman cycle begins at Zi and runs to Hai, completing one round; the six Yang and six Yin phases begin and end as one.

The Primordial Lord says: “The talisman uses the hexagram lines.” The water-and-fire talisman follows a rhythm of six Yang and six Yin. In each twelve-hour cycle, it passes from the civil to the martial stage. As Yang grows and Yin diminishes, the first civil stage begins with one line, like the birth of a single Yang line in the center of Kan. The martial stage ends at the fifteenth line, like the birth of two Yin lines in Li. When Yang reaches its height, the pattern follows the Great Strength hexagram. The tally then completes its cycle, so the process begins at Zi; count six talismans as they arise, and together they form the beginning. This corresponds to one line within Yin, while the Yang talisman gradually adds one line. From Zi to Si, it lies concealed, entering the third position. Chen and Si form one Qi, so fire is born in Chen and Si. It then withdraws and remains guarded for sixty hours, ending at Xu and Hai, before beginning again at Zi. The Hidden Jia Scripture says: “In advancing and retreating, when meeting the sovereign, the martial stages turn away from one another.”

Note for ease of reading

“Lead,” “mercury,” “gold,” “seed,” “mother,” and “two eights” are mostly Neidan metaphors, rather than references simply to refining ore. “Earthen crucible,” “spirit chamber,” “escaping the womb,” and “Fire Elixir” refer to vessels, the regulation of fire, and successive stages of cultivation. “Talisman,” “hexagram line,” and the cycle from Zi to Hai link the hours with hexagram images and the waxing and waning of Yin and Yang; together, they form a system of instructions for choosing times and regulating the fire.

Daoist Pivot: A Modern Interpretation

Yang Qi is above, following the text from beginning to end; Yin Qi is below, returning in cycles.

This describes the positions and cycles of the two Qi, Yin and Yang. Yang Qi tends to be above and moves according to a regular pattern; Yin Qi tends to be below and turns back and forth. After the winter solstice, when the day’s stem is Jia (the first of the ten Heavenly Stems, here marking the point when Yang begins to arise in the correspondence between solar terms and the stem-branch cycle), Yang Qi grows upward from below. After the summer solstice, when the day’s stem is Jia, Yin Qi grows downward from above. That is why the scripture says the Direct Talisman (a use of “Heavenly Talisman” aligned with celestial timing and the images of the trigrams) has an upper talisman and a lower talisman, selected by month (without being fixed to a particular year or an unchanging set of seasons).

The scripture also says that, beginning with the first pentad, a line is activated at the hour of Zi (the first of the twelve double-hours, corresponding to rat), following the lines of a hexagram. After completing a full cycle, it returns to Zi, corresponding to one line within the Heavenly Talisman. This line corresponds to one of the twenty-four solar terms. In maintaining this practice, roughly two and a half days make one Qi, and the Qi gradually accumulates. Five days make one pentad; after sixty double-hours have accumulated, one cycle ends in the Chen-Si period, and another ends in the Xu-Hai period. From Yin to Shen is seven returns; from Zi to Shen is nine reversals—one rise and one fall. Zhen and Xun are the first of Jia, the foundation of Fire, and the hub through which the Five Phases interact. Qian, Kun, Zhen, and Xun, joined above and below, form the “forbidden gate”—the key point—for generating Jia.

The scripture says: when a line moves, Qi accumulates in divisions of two and a half days. After five days make one pentad, only two hexagrams are used to accord with the profound celestial pattern; this is the Heavenly Talisman.

The day is the Heavenly Talisman, the month is the Yin Talisman, and Fire is the Earth Talisman. The adjustments to the seasonal talisman advance or retreat according to the clepsydra (timekeeping); adjustments to the moving talisman depend on the sequence and mutual alignment of Qi (the coordination of Yin and Yang in their proper order). One must also follow the Seven Luminaries (the sun, moon, and five planets), the Five Phases, the Celestial Pivot (the movement of the heavens), the stellar lodges and their degrees, as well as the lengths of lunar months and leap months, to determine the rises and falls. The process begins with Fu and Zhen, passes through Xun, and ends at Kun. It all depends on the reciprocal activity of Yin and Yang; that is the method.

The Yellow Emperor’s Hand Mirror says: count its pattern by the day, like a wheel turning on its axle. One hundred and eighty jin of Fire represents the number of nine times nine (9 × 9 = 81, or perhaps a numerical scheme involving 180 double-hours). What are the Three Cycles?

Five days and sixty double-hours make the upper cycle; ten days and one hundred and twenty double-hours make the middle cycle; fifteen days and one hundred and eighty double-hours make the lower cycle.

On days of Jia or Ji, Jiazi arises at midnight. On days of Yi or Geng, Bingzi arises at midnight. On days of Bing or Xin, Wuzi arises at midday. On days of Ding or Ren, Gengzi arises at midnight. On days of Wu or Gui, Renzi arises at midday.

The first Jiazi after the winter solstice marks the upper cycle. At Wuchen (five days, or sixty double-hours), the upper-cycle Jiazi is in operation; this is the Four Central Signs (perhaps the four cardinal positions; the text may mean the four cardinal times). At midnight on the days of the Four Central Signs, Jiazi arises and proceeds through one-eight palace; Tianpeng takes charge. These are Zi, Wu, Mao, and You.

From Jisi through Guiyou … (the original scroll continues below with the middle and lower cycles and their correspondence to the trigrams, palaces, and presiding forces.)

Note for understanding the passage: This text belongs to a group of Daoist writings on internal cultivation, talismans, trigrams, and the observation of Qi cycles. It uses hexagram lines, solar terms, the stem-branch cycle, the Three Cycles, and the Nine Palaces (such as Tianpeng) to determine when to “activate a line” and when to align with a talisman. It takes account of the ordinary calendar, leap months, and the divisions between day and night.

Over five days, or sixty two-hour periods, the cycle runs through the Upper Yuan Jiazi and is called the Four Meng. During the Four Meng, between midnight and the Zi hour, it passes through palaces four, three, and two. The Tianren star is in charge, corresponding to the four periods Yin, Shen, Si, and Hai.

From Jiaxu through Wuyin, over five days or sixty two-hour periods, the cycle runs through the Lower Yuan Jiazi and is called the Four Seasons. During the Four Seasons, between midnight and the Zi hour, it passes through palaces seven, six, and four. The Tianfu star is in charge, corresponding to the four periods Chou, Xu, Wei, and Chen.

At the summer solstice, it then moves in reverse through the Nine Palaces, repeating the cycle. After completing one month, or three hundred and sixty two-hour periods, it brings the timing of the firing process into alignment with the seasonal markers. This symbolizes the practice of the four seasons of the year.

(The mnemonic says: Take a small porcelain bottle and make a hole the size of a bean in its base. Place it inside a crucible. Use finely sifted, calcined Wuji earth as a covering, and put sand of bright texture and even color into the porcelain bottle. Set it over the crucible and seal it firmly with Liuyi clay. Heat it beneath with charcoal. Once the porcelain bottle grows hot, first plug the hole with a twisted paper wick, then pull it out at the proper time. If white smoke emerges, that is mercury; plug the hole again, and continue until no more white smoke appears. The next day, take out the porcelain bottle and collect the mercury with a chicken feather brush. If the sand has not yet turned red, continue collecting it by the method described above until all the mercury in the sand has been extracted.)