《易外别传(俞琰)》

The Yiwai Biezhuan discusses the hidden secrets contained in the circular schema of the Xiantian Diagram, belonging to the teachings of the Han Confucian Wei Boyang as set forth in his Cantong Qi. Human beings live between heaven and earth: the head belongs to Qian and the abdomen to Kun; exhalation resembles the sun and inhalation the moon. The body undergoes the same transformations of Yin-Yang as heaven and earth themselves. The Yi (Classic of Changes) is employed to elucidate the Dao (the Way) of Yin-Yang, and thus Wei Boyang drew upon the Yi to expound his doctrine, whose essential contents do not go beyond the Xiantian Diagram. Although this represents merely a leftover strand of the Dao of the Yi, it remains an important element in the gentleman’s nourishing of life and therefore cannot be left unknown.

The wonder of the Xiantian Diagram consists in joining the conclusion of the Kun hexagram to the opening of the Fu hexagram, circulating without pause or exhaustion. A still deeper wonder lies in the interval of conjunction between Kun and Fu, that is, at the precise moment when movement and stillness interchange. I once devoted myself to this study and read through the related texts, yet grasped only a fragment. Later I chanced to meet a recluse who transmitted to me the method of reading the Yi, and only then did I apprehend the secret meaning of the circular diagram. Returning to observe it within my own person, I discovered that what Shao Kangjie (the Northern Song scholar of the Yi, Shao Yong) called Taiji (Supreme Ultimate), the Heavenly Root and Lunar Cave, and the Thirty-six Palaces all have their correspondences inside the body. This is what is meant by “the Yi within the body.” I have now drawn it as a diagram and appended the remarks of earlier Confucian scholars so that the principles stand forth clearly; the reader will understand at a glance, and those of insight will naturally take it in.

Written on the fifteenth day of the eighth month in the jia-shen year of the Zhiyuan era by Yu Yan, the Daoist of Shijian from ancient Wu.

Taiji

Shao Kangjie said: “The heart is Taiji.”

Zhu Ziyang (the Southern Song Neo-Confucian Zhu Xi) said: “Taiji is the image of emptiness occupying the center.”

Xiantian Diagram

The Cantong Qi (a Daoist Neidan (internal alchemy) classic) states that the year concludes with the Kun hexagram and recommences from the Fu hexagram, cycling round and round like a ring joined into a circle. Shao Kangjie (a Song dynasty scholar of the Yijing) wrote in a poem: “Once I had grasped the principle at the center of the ring, all the disordered Qi (vital energy) in my chest completely dissipated.” He further said: “When the Qian hexagram encounters the Xun hexagram, one may observe the Moon Cave; where the earth meets the place of thunder’s stirring, one can see the Heavenly Root. The Qi between the Heavenly Root and the Moon Cave comes and goes freely of itself, and spring fills every place among the Thirty-Six Palaces.”

I am of the opinion that the Moon Cave is above and the Heavenly Root below; that which comes and goes between the Moon Cave and the Heavenly Root is the heart-mind. The so-called “Thirty-Six Palaces” refer to the Bagua (Eight Trigrams): Qian as one, Dui as two, Li as three, Zhen as four, Xun as five, Kan as six, Gen as seven, and Kun as eight. To say that “the Thirty-Six Palaces are all spring” is to say that harmonious Qi flows throughout the entire body. Viewed in this way, the Thirty-Six Palaces are not to be found in the diagrams of books, but within our own bodies. This principle was understood by Shao Kangjie and Zhu Ziyang (an alternative name for Zhu Xi), yet ordinary Confucian scholars who merely read the chapters and verses of books do not understand it.

Shao Kangjie stated in the Huangji Jingshi Shu: “The Xiantian Tu (the Yijing diagram arranged according to the sequence of the Pre-Heaven Bagua) is the center of the ring.” I consider that the human body itself is the Xiantian Tu. The heart-mind is situated at the center of the body, just as Taiji (Supreme Ultimate) is situated at the center of the Xiantian Tu; what Zhu Ziyang referred to as “the empty space in the middle” points precisely to this. The Xiantian Tu begins from the Fu hexagram and ends with the Kun hexagram, head and tail joining, like a ring, and is therefore called a “ring.” The so-called “center of the ring” means that the sixty-four hexagrams encircle the outside while Taiji occupies the center. In the Yi, the center is Taiji; in the human body, the center is the heart-mind. Once one understands that the heart-mind is Taiji, one may speak of the Dao (the Way).

It is further said: After the winter solstice comes “exhalation,” and after the summer solstice comes “inhalation”; this constitutes the breathing of Heaven and Earth over the course of one year.

Zhu Ziyang (Zhu Xi) said: “Between heaven and earth there is only a single current of Qi (vital energy). From this year’s winter solstice to next year’s winter solstice is like one complete breath: exhalation is Yang, inhalation is Yin.” I consider that after the winter solstice the hexagrams evolve gradually from Fu to Qian, belonging to Yang and thus compared to exhalation; after the summer solstice the hexagrams evolve gradually from Gou to Kun, belonging to Yin and thus compared to inhalation. Exhalation means Qi issuing outward, corresponding to the time after the winter solstice; inhalation means Qi being drawn inward, corresponding to the time after the summer solstice. In a broad sense this is the annual breathing of heaven and earth; in a narrow sense it is the inhalation and exhalation of the human body. The Cantongqi (a Daoist Jing of cultivation) says: “The dragon breathes toward the tiger, and the tiger absorbs the Jing (essence) of the dragon.” It also says: “Breathing mutually contains and nourishes, waiting quietly like husband and wife.” Here breathing is likened to dragon and tiger as well as to husband and wife. Although the metaphors in the various classics and discourses are many, in the final analysis they speak only of breathing.

It further remarks: “One movement and one stillness—is this not perhaps the subtlest principle in the universe? In the interval of one movement and one stillness, heaven, earth, and humanity communicate with nature—is this not perhaps the subtlest principle?”

Zhu Ziyang said: “The left of the diagram belongs to Yang, the right to Yin.” I consider that the left side of the diagram, running from Fu to Qian, indicates the stirring of Yang Qi; the right side, running from Gou to Kun, indicates the quiet settling of Yin Qi. The critical juncture of alternating movement and stillness is at the close of Kun and the opening of Fu, that is, the meeting place of Yin-Yang: within a year it corresponds to the winter solstice, within a month to the dark moon and new moon (the transition at month’s end and beginning), within a day to the end of the Hai hour and the start of the Zi hour (the nighttime boundary). Meng Kang stated: “The Zi hour lies to the west, the Hai hour to the east, and the space between them is the boundary.” I consider that when Qian and Kun in the human body (referring here to the locations and states of Yin-Yang intersection within the body) reach the utmost of stillness, the opportunity for movement then arises and resonates with the opportunity in the movements of heaven and earth; this truly is the subtlest principle linking heaven, earth, humanity, and nature.

It is also said: “Still and unmoving” is because there is no Yang Qi, just as in the image of the Kun hexagram; “stimulated, it then communicates with the reasons of all under heaven” is Yang Qi stirring internally, just as in the meaning of the Fu hexagram.

I believe that “stillness” is quietude taken to the extreme, belonging to the purely Yin Kun hexagram; “stimulation” is the beginning of movement, belonging to the Fu hexagram in which Yang Qi first arises. Between “stillness” and “stimulation” is the transformation of one movement and one stillness.

It is also said: “Before Wuji, Yin contains Yang; after there are images, Yang divides Yin.”

Zhu Ziyang (Zhu Xi, courtesy name Ziyang) said: Shaozi (Shao Yong) used diagrams to illustrate the principle of Yin-Yang circulation. From the Gou hexagram to the Kun hexagram is Yin containing Yang; from the Fu hexagram to the Qian hexagram is Yang dividing Yin. Between the Kun hexagram and the Fu hexagram is Wuji.

Yuan Jizhong said: Master Zhu holds that between the Kun hexagram and the Fu hexagram is Wuji; this insight is exceedingly subtle. He also wrote in a poem: “Suddenly at midnight a clap of thunder, ten thousand doors and a thousand gates open in succession. If you recognize that within nothing there is contained an image, I permit you to personally see Fu Xi coming.” This means that within the formless there is form, which is precisely the state between the Kun and Fu hexagrams, that is, Taiji (Supreme Ultimate) arising from Wuji. Shao Yong’s teachings, if not for Master Zhu, who else could have elucidated them?

Shao Yong also wrote in the “Winter Solstice Chant”: “The winter solstice is in the middle of the zi month; the movement of the heavenly heart has never changed. When Yang Qi has just begun to stir, the myriad things have not yet been born. The sacrificial dark wine (clear water, which the ancients used in place of wine for sacrifices) has a bland flavor; the grand sound is instead heard as scarce.” This is saying: if you do not believe these words, you might as well go ask Pao Xi (Fu Xi) again.

He also said: “What is called the ‘mechanism’? The principle contained in the heavenly root (the root of Yin-Yang change) is extremely subtle. The place where this year is about to end is precisely the time when tomorrow begins anew. This crucial juncture is easy to grasp in its meaning, yet difficult to express in words. If a person can understand this principle, what else could they not understand?”

He also wrote in a poem responding to Professor Wei: “Whenever reading books I reach the place of the heavenly root, I often worry that you gentlemen will ask about the most mysterious principle.”

Zhu Xi said: “Half of the zi hour has not yet fully entered the zi hour, precisely at the moment of just leaving the hai hour.” He also said: “The place where one yang first begins to stir is at the juncture of zhen and yuan.” I believe this is exactly where the vital mechanism of creation begins to manifest. This principle is extremely mysterious, often making one worry that someone might inquire into its secrets.

Zhu Xi said: “Half of the zi hour has not yet fully entered the zi hour, precisely at the moment of just leaving the hai hour.” He also said: “The place where one yang first begins to stir is at the juncture of zhen and yuan.” I believe this is precisely the true subtle mechanism of the operation of creation. Cheng Yi said: “If one has not glimpsed the essential workings of creation, how could one speak of the way of longevity?”

Shao Kangjie wrote in the Huanghu Yin: “Yin-Yang begin to transform in the midst of the indistinct and vague, the breaths of Heaven and Earth intermingle and suddenly swirl. In that interval there is a momentary beautiful scene; how can it be clearly expressed in words and effort?”

I believe Shao Kangjie’s poem has already fully expressed the most profound mystery of the Heavenly Root. If one has not personally entered the realm of the indistinct and vague and truly reached the domain where the Qi of Yin-Yang intermingles, how could one know how mysterious it is?

The Straight Diagram of the Former Heaven Sixty-Four Hexagrams

The Qian hexagram is above and the Kun hexagram below; this is the pattern of Heaven and Earth each settling in their proper positions. The Kan and Li hexagrams take the middle lines of Qian and Kun and therefore occupy the center.

Shao Kangjie said in the Huangji Jingshi Shu: “The root of Heaven and Earth probably begins from the middle. Therefore although Qian and Kun change repeatedly, they never depart from the center.”

He also said: “From below upward is called ascent, from above downward is called descent. Ascent means growth, descent means decline. Therefore yang Qi arises from below and yin Qi arises from above, so all things turn from decline to generation.”

He also said: “Yang is born within yin, yin is born within yang; yin again generates yang, yang again generates yin, therefore the transformations cycle back and forth without end.”

The Qiankun Yin further says: “The Dao is not far from people; Qian and Kun are within oneself. Who would go outside Heaven and Earth to seek Qian and Kun elsewhere?”

I believe that Qian and Kun represent pure Yin and Yang, while Kan and Li represent the intermingling of Yin and Yang. Qian, with all six lines yang, symbolizes Heaven and is therefore placed above the central position; Kun, with all six lines yin, symbolizes Earth and is therefore placed below the central position. Kan contains yang within yin and symbolizes the Moon; Li contains yin within yang and symbolizes the Sun. Thus Kan and Li lie between Qian and Kun.

The remaining sixty hexagrams follow as a single yang is born within Kun and yang Qi (vital energy) gradually increases until five yang lines are reached, attaining the peak of ascent and becoming Qian with six yang lines. As a single yin is born within Qian, yin Qi gradually increases until five yin lines are reached, attaining the peak of descent and becoming Kun with six yin lines. Yang Qi rises and yin Qi descends, circulating up and down without cease.

Heaven, Earth, and the human body operate in the same manner. At the zi hour (midnight) Qi travels to the weilu (the base of the spine); at the chou and yin hours it reaches the waist; then it arrives at the niwan (an internal alchemy term for a point in the head)… At the wei, shen, and you hours it reaches the chest and diaphragm, finally returning to the abdomen. This describes the rising and falling of Qi over the course of a day. Breathing follows the same pattern: when inhaling, Qi rises from below and afterward descends from above. In terms of heavenly time it corresponds to the zi and wu hours; in terms of earthly Qi it corresponds to the tides, whose changes likewise accord with zi and wu. The zi and wu hours occupy roughly the middle of the movements of Heaven and Earth.

The Cantong Qi (a Daoist classic of Neidan (internal alchemy)) states: “Unite the tally and proceed in the center.” It also says: “Do not lose the center.” And further: “One must know the center within one’s own body; Qian and Kun are not located between Heaven and Earth.” Only upon meeting someone who understands the principles of transformation can one discuss the Qian and Kun within the body and thoroughly investigate the “center” within oneself! [The original text here contains errors and omissions, making some of the meaning difficult to determine with certainty.]

The Yi says: “The supreme Kun-yuan enables the growth of all things; it follows and receives the movement of Heaven.”

The Cantong Qi says: “Always follow the patterns of the Earth, receiving and disseminating teachings among humanity.”

I believe that a person's original Qi (the fundamental vital energy of life) is stored in the abdomen, just as the myriad things are stored within Kun earth. When Shen (spirit) enters the lower part of the body, it is like the Qi of Heaven descending to Earth. When Qi and Shen unite, it is like the Dao of Earth receiving the Dao of Heaven. Heaven and Earth rely on this relationship to generate and nourish the myriad things, and my body likewise relies on this relationship to refine the elixir. The Taixuan Jing says: “Hide the heart in the deep abyss, and the root of spiritual nature thereby becomes excellent.” This statement conveys the same meaning as here.

Diagram of the Moon Receiving the Sun’s Light

Shao Kangjie said: The moon is originally black; it appears bright only upon receiving the light of the sun.

I believe that the sun belongs to Yang and the moon to Yin. The moon itself has no light; its light actually comes from the sun. Yang is bright and Yin is dark; Yang bestows and Yin receives, therefore Taiyin (the moon) receives the light of the sun and thereby possesses brightness. A person’s heart is like the sun, and the Qihai (the place in the lower abdomen where Qi is stored) is like Taiyin. When the heart is settled, Shen coalesces; when Shen coalesces, Qi gathers. If a person can cause Shen to condense and enter into the Qi, then Qi and Shen will unite, just as Taiyin receives the light of the sun.

Diagram of the Prenatal Trigrams with Qian Above and Kun Below

Diagram of the Postnatal Trigrams with Li in the South and Kan in the North

Shao Kangjie said: Shen is commanded by the heart, Qi is commanded by the kidneys, and the physical form is commanded by the head; form and Qi interact, with Shen residing in the center as the ruler. This is the Dao of the Three Powers of Heaven, Earth, and Humanity.

I believe that the human body can be analogized to Qian (Heaven, Yang) and Kun (Earth, Yin): the head belongs to Qian, the abdomen to Kun, and the heart occupies the middle, its position exactly like that of “Human” among the Three Powers of Heaven, Earth, and Human. The kidneys govern the Qi (vital energy) within the body, while the head governs the physical form; occupying upper and lower positions respectively, they originally cannot communicate. What enables them to interact is Shen (spirit) (here referring to inner spiritual activity). When Shen circulates in the center of the body, the Qi of above and below merge and interpenetrate, in harmony with the movements of Heaven and Earth. Is this not the Dao of the Three Powers?

When Shen is guarded in the kidney region, it quietly stores and conceals itself, which is the Kun Dao; when Shen is guarded in the head, it actively circulates, which is the Qian Dao. Storing and concealing allows the subtle substances to coagulate; unceasing circulation resembles the Zhoutian cycle. The coagulated subtle substances are called “medicine,” and the unceasing circulating operation is called “fire.” Here “medicine” and “fire” are terms in Neidan (internal alchemy) cultivation, respectively referring to the coagulated Jing (essence) and Qi during practice and the function that propels their circulation.

The Yinfu Jing says: “The key lies in the eyes.”

Shao Kangjie (a Northern Song Neo-Confucian scholar) said: “The spiritual brightness of Heaven manifests in the sun; the spiritual brightness of humans manifests in the eyes.”

I believe that wherever the gaze is directed, the heart-Shen follows. Therefore the method of inner cultivation is to look at the nose with the eyes and then align the nose with the navel, causing the heart-fire to descend to the Qihai (the Dantian [energy center] below the navel). This is a practice that can be accomplished in but a moment.

The Yi Jing says: Qian represents Heaven, Kun represents Earth, Li represents the sun, Kan represents the moon; it also says: Qian represents the head, Kun represents the abdomen.

The Taixuan Jing says: Yang Qi quietly germinates in the Yellow Palace. The Huangting Jing says: “If you wish to live long without dying, you should cultivate Kunlun (here referring to the head).”

It also says: “When the sun rises and the moon sets, the breath should still be maintained.”

I believe that the head, situated above and round in form, is the gathering place of all yang Qi (vital energy) and thus symbolizes Qian Heaven; for this reason the Yi Jing (Book of Changes) correlates the Qian hexagram with the head. Mount Kunlun lies in the northwest, the Qian position, and therefore the Huangting Jing (Yellow Court Scripture) calls the head “Kunlun.” The abdomen, situated below and occupying the center of the body, is hollow within and is the gathering place of the eight meridians, thus symbolizing Kun Earth; for this reason the Yi Jing correlates the Kun hexagram with the abdomen. Heaven’s color is a deep black while earth’s color is a yellowish brown, and therefore the Taixuan (Great Mystery) refers to Kun as the “Yellow Palace.”

The sun rises in the east and the moon rises in the west, so the Yi Jing correlates the Li hexagram with the sun and the Kan hexagram with the moon. Breath enters and exits; Qi rises and descends, circulating without pause. Therefore the Huangting Jing correlates breathing with the sun and moon. Some people liken the two eyes to the sun and moon, but this view is incorrect: the eyes possess only the form of the sun and moon, not their function of movement.

The Cantong qi (Token for the Agreement of the Three), a classic of Daoist cultivation, states: “Nine returns and seven comes back; eight returns and six abides.” It also says: “Seven and eight added together make fifteen; nine and six likewise correspond to each other.” And further: “Where Metal and Water join, Wood and Fire take the lead. The four blend into one and are arrayed as dragon and tiger.” Here Metal, Water, Wood, and Fire are terms employed in Daoist Neidan (internal alchemy) to describe the processes of Qi transformation and inner cultivation.

I believe that six, seven, eight, and nine are the completing numbers (the numbers that mark the maturity and settled form of things) corresponding respectively to Water, Fire, Wood, and Metal. The completing number of Wood is eight, which belongs to “correspondence.” [Note: At this point the original text becomes repetitive and the connection is incomplete; the quoted lines such as “where Metal and Water join, Wood and Fire take the lead” have already appeared earlier.]

I believe that six, seven, eight, and nine are the completion numbers of Water, Fire, Wood, and Metal. The number of Wood is eight, belonging to the East; the number of Fire is seven, belonging to the South. The Wood Qi (vital energy) rises from the East and thus resonates with the Fire Qi of the South. The number of Metal is nine, belonging to the West; the number of Water is six, belonging to the North. The Metal Qi descends from the West and thus merges with the Water Qi of the North.

What the Neidan (internal alchemy) practitioners (Daoist cultivators of internal alchemy) call the “Red Dragon” and “Black Tiger” are metaphors: when the seven mansions of the Azure Dragon of the East move to the South, they are called the Red Dragon; when the seven mansions of the White Tiger of the West move to the North, they are called the Black Tiger. These sayings are all merely used to analogize the breathing within the body. If we pursue it to the end, where truly are there dragons and tigers? Where truly are there Metal, Water, Wood, and Fire? Where truly are there seven, eight, nine, and six? They are all just metaphors.

Some people wonder: nine, seven, and eight are respectively said to “return,” “revert,” and “go back,” why does six alone say “reside”? Is there perhaps some difference? The answer is: the Water Qi represented by six resides in the North and does not move; the Qi of the other three directions, whether “returning,” “reverting,” or “going back,” ultimately all gather in the North, therefore it is said to “reside.”

Diagram of the Cyclic Ascent and Descent of the Twelve Hexagrams in the Interchange of Qian and Kun

Qian is above and Kun is below, symbolizing the Heaven and Earth within my body. Tai is on the left and Pi is on the right, symbolizing the ascent and descent of the Qi of Heaven and Earth within my body. Fu does not refer to the eleventh month of the lunar calendar, nor is it the midnight zi hour, but rather refers to the “zi” within the body; Gou does not refer to the fifth month of the lunar calendar, nor is it the noon wu hour, but rather refers to the “wu” within the body. Zhang Wuzhen said: “When Pi and Tai interchange, the Qi of Yin-Yang then has ascent and descent.” This is precisely speaking of the changes of Tai and Pi within the body.

Diagram of the Cyclic Ascent and Descent of the Twelve Hexagrams in the Interchange of Kan and Li

Kan in the north and Li in the south symbolize the water and fire within my body. The hexagram Jiji symbolizes the joining of water and fire, while Weiji symbolizes water and fire that have not yet joined; these two hexagrams speak of the rising and falling of water and fire inside the body.

The hexagram Zhun corresponds to the yin hour, and Meng to the xu hour; they refer to the fire phasing, or huohou, within my body (the arrangement of process and timing during cultivation). The “yin” here is not the yin hour at daybreak, nor is “xu” the xu hour at dusk; they indicate the corresponding moments within the body. Zhang Wuzhen said, “The application of the two hexagrams Zhun and Meng has movement and stillness, like morning and evening.” This is precisely the Zhun and Meng of my own body.

The Cantong Qi says: “On the morning of the new moon, the hexagram Zhun takes charge; by evening, Meng takes over. Day and night each use one hexagram, operating in succession. When Jiji and Weiji have run until just before dawn, that cycle comes to an end, after which it begins again from the hexagram Fu.” Here the cycle of days and hours is taken as the period of operation, with movement and stillness each having their morning and evening. In spring and summer one follows the inner mode of operation, from the zi hour to the chen and si hours; in autumn and winter one adopts the outer mode of operation, from the wu hour through the xu and hai hours.

I believe that the Cantong Qi analogizes Qian and Kun to the ding (the vessel for refining the elixir), Kan and Li to the medicines, and draws on the remaining sixty hexagrams to illustrate the fire phasing (the regulation of fire intensity and duration in the alchemical process). A day consists of twelve double-hours, and two hexagrams together contain twelve lines, therefore two hexagrams are used each day: morning corresponds to Zhun, evening to Meng; morning to Xu, evening to Song, and so forth all the way to Jiji and Weiji.

Zhun turned upside down is Meng, symbolizing one ascent and one descent. Zhun rises from the interior toward the exterior, corresponding to morning, the daylight hours, and spring and summer; Meng descends from the exterior toward the interior, corresponding to evening, the nighttime hours, and autumn and winter. The remaining hexagrams may all be understood in this manner.

Is it permissible to distribute the sixty hexagrams over thirty days in order to represent a month? What then if one encounters a short month of only twenty-nine days? This is merely a metaphor and does not mean that the process must actually be scheduled according to thirty days. Some interpret it as a technique of shutting the eyes and counting the breaths, which would prove both tedious and exhausting—how could that ever be regarded as the utterly simple and easy Dao (the Way)?

The Diagram of the Myriad Distinctions Returning to a Single Source of the Golden Elixir Cauldron, Medicines, and Fire Phasing in the Zhouyi Cantong Qi

The profundities within it are extensive and far-reaching; they must be examined with care, which is indeed laborious. These are no idle or false statements, but lucid and trustworthy principles.

This teaching, transmitted even after a hundred million generations, remains clearly attestible; luminous as the stars coursing through the Milky Way, boundless as the waters converging into the sea.

One must ruminate over it repeatedly in thought so that understanding ripens; collate it from top to bottom again and again. After a thousand recitations the principles of the medicines emerge of themselves with clarity; after ten thousand they are committed to memory. The spirits and gods may perhaps disclose the teaching to a person, or one may suddenly attain insight in the mind.

By exploring the origin and pursuing the connections, the path of initiation is found. The heavenly Dao has no predetermined favoritism; it is always passed on to the worthy and enlightened.

The above is a revised edition of Peng Zhenyi’s Mingjing Tu (Bright Mirror Diagram); with minor additions and deletions upon this foundation, the Nine-Ring Diagram was drawn.

The Yi states: “The Dao of Heaven moves with vigor and never ceases; the gentleman should thereby spur himself on, never coming to a halt.”

Hu Anding said: “Gazing upward at the sky from the earth, the color one sees is bluish-green. The south pole extends thirty-six degrees below the earth’s surface, while the north pole rises thirty-six degrees above it; the overall form resembles a pestle leaning at a slant. This is the shape of Heaven. As for the movement of Heaven, in the course of one day and one night it travels more than nine hundred thousand li. A person’s single exhalation and inhalation is called one breath; in the time of one breath, Heaven has already traveled more than eighty li. By the time a person completes a full day and night, Heaven has traveled more than nine hundred thousand li, from which one can see how vigorous the movement of Heaven is.”

He also said: “When a person’s Shen (spirit) and Qi (vital energy) gather together, one lives; when they scatter and disperse, one dies. Heaven possesses a vigorous, yang Qi that circulates without cease, and therefore the heavenly body is able to endure for a long time.”

According to what is said in the Cantong qi (a Daoist classic): “The pivotal axis has a high and a low, and thus the entire heavenly body turns accordingly.” The pivotal axis refers to the north and south poles; the complete circuit of Heaven refers to the twenty-eight lunar lodges (the stellar regions into which the ancients divided the sky); rushing about means movement. The form of Heaven is like a pellet, revolving around the complete circuit of Heaven day and night without pause; the north and south extremities, one high and one low, constitute the pivotal axis. The human body is the same: above there is the heavenly pass, below there is the earthly axis. If one can turn the heavenly pass and set the earthly axis in motion, then in the coming and going between above and below, a single breath can complete one full circuit of Heaven.

I further follow what is said in the Cantong qi: “Revolving along the handle of the Dipper, rising and falling.” Here “huanji” refers to the Northern Dipper. Heaven takes the Northern Dipper as its pivotal mechanism; the human being takes the heart as its pivotal mechanism. The heart moves within the body just as the Northern Dipper moves within the heavenly body.

I further follow what is said in the Yinfu jing (a Daoist classic): “Observe the Dao (the Way) of Heaven and grasp the laws of its movement; this is sufficient.” This is because the human Dao communicates with the Dao of Heaven. If a person can gather and restrain the heart-Shen…

I have also examined what the Yin Fu Jing says: “Observe the Dao (the Way) of Heaven, master the laws of Heaven’s movement, and one can grasp everything.” This is because the principles of humanity and the Dao of Heaven are originally interconnected. If a person can withdraw the faculties of sight and hearing, return the mind and Shen (spirit) to profound stillness, regulate the coming and going of the breath so that the Qi (vital energy) circulates without cease, then one can move in unison with the Dao of Heaven and thereby grasp the key to Heaven’s operations. Nevertheless, while the Dao of Heaven can be observed, the laws of Heaven’s movement are not easily mastered. Who can master them? Only those whose mental state is empty and still.

The Yi Jing says: “The superior person is inwardly substantial and thereby penetrates the principles of affairs; occupying one’s proper position with rectitude, the inner De (Virtue/Power) is stored within; it further manifests in the deportment of the four limbs and in one’s enterprises and actions—this is the realm in which De is fully displayed.”

Xu Jinzhai stated that those who cultivate Neidan (internal alchemy) also borrow this layer of meaning.

Wei Boyang says in the Can Tong Qi: “The yellow center gradually penetrates the principles, and the moistening Qi reaches the skin.” Yet the intended meanings of the two passages differ. The Yi Jing passage speaks of understanding principle and righteousness and of nourishing the inner mind; it is spoken from the public laws of the Dao of Heaven. The Can Tong Qi speaks of preserving and firmly protecting one’s own Jing (essence) and Qi; it is spoken from the standpoint of individual cultivation.

I believe that when the Can Tong Qi cites the Yi Jing, it is merely borrowing the principles of the Yi to clarify its own meaning, and does not necessarily adopt the original sense of the Yi Jing text in every instance. The Yi Jing resembles Heaven and Earth, and the human body likewise resembles Heaven and Earth, so Wei Boyang borrowed the Yi Jing to compose the Can Tong Qi. “Yellow center” refers to the yellow path within the body, a technical term in Neidan cultivation.

The Yi Jing further says: “If an error can be corrected while it is still not far advanced, there will be no great regret, and the outcome will be auspicious.”

Zhu Ziyang said: “The Laozi states that in governing the people and serving Heaven’s Dao (the Way), there is no better method than cherishing one’s vital energy. Only by achieving this cherishing can it be called ‘zaofu.’ Zaofu means regulating and nourishing at an early stage. Zaofu is also called ‘chong ji De.’”

Zhu Ziyang explained this meaning very thoroughly. “Zaofu” means being able to plan ahead so that the timing for nourishment will not be missed; “chong ji De” means that one already possesses some accumulation, and then by further cherishing and nourishing it one adds still more to the existing store.

Taking the cultivation of the body as an example, if the body has not yet suffered any depletion and one promptly cherishes and nourishes it, this is called zaofu and is likewise a form of repeated accumulation of De (Virtue/Power). If one waits until the body has already been damaged before beginning to nourish it, the effect of nourishment is merely to make up for the loss and cannot be called “repeated accumulation.” Therefore what is precious is zaofu: perceiving the situation early and taking protective care while the body has not yet incurred any depletion.

In a case such as my own, the body has already grown weak and depleted, like a dilapidated house leaning this way and that; even if I wish to cultivate it, how much benefit can there really be? This year I received a letter from Cai Jitong. He said that recently he has thoroughly understood the principles of nourishing life and has also mastered the methods, yet his physical condition is already like a crumbling city wall, making it difficult to apply the practice. It seems this is indeed so.

I further consulted Zeng Zhiyou’s Jixian zhuan. The book states that Zhou Cong was a native of Sizhou. Xu Shenweng held him in high regard and once said: “I myself only married when I was already a young man; this person attained the Dao while still very young, his Jing (essence) and Shen (spirit) being complete and abundant—I cannot compare with him.” A person such as Zhou Cong is probably one of those whom the Laozi describes as having nourished themselves early and continually accumulated.

I also examined the Suwen: at the age of eight a boy’s kidney Qi (vital energy) becomes full, the hair begins to grow, and the milk teeth are replaced; at sixteen the kidney Qi is vigorous, the tian’gui (the Jing related to reproductive maturity) arrives, the Jing-Qi is abundant, Yin-Yang are in harmony, and therefore he is able to… This too, I suppose, can illustrate why one should nourish and accumulate Jing-Qi at an early stage.

I further refer to the Suwen (the medical classic within the Huangdi Neijing) to illustrate: in males, at the age of eight, Kidney Qi (vital energy) is replete, hair begins to grow and the milk teeth are replaced; at sixteen, Kidney Qi is vigorous, Tianguì (the Jing [essence] that promotes maturation of the reproductive functions) arrives, Jing-Qi is abundant and can be discharged, Yin-Yang unite in harmony, and thus one is able to beget children; at twenty-four, Kidney Qi is harmonious, sinews and bones are strong, wisdom teeth emerge and physical development reaches its peak; at thirty-two, sinews and bones are robust and the muscles are full; at forty, Kidney Qi begins to decline, hair falls out and the teeth wither; at forty-eight, Yang Qi in the upper body weakens, the complexion becomes haggard and the hair at the temples turns gray; at fifty-six, Liver Qi weakens, the activity of the sinews and vessels is no longer agile, Tianguì is exhausted, Jing-Qi diminishes, the Kidneys decline and all bodily functions have entered a stage of weakness; at sixty-four, the teeth and hair fall out.

The Suwen further says: those of high antiquity who understood the Dao (the Way) of nourishing life followed the transformations of Yin-Yang, attuned themselves to the principles of nourishing life, were moderate in diet, regular in daily routine and did not overexert themselves; thus physical form and Shen (spirit) could coordinate with each other, they lived out their allotted span and passed away only after exceeding a hundred years. People of today are not like this: they treat wine as if it were a watery slurry and are habituated to unrestrained indulgence; after becoming drunk they still engage in sexual activity, allowing desire to exhaust Jing-Qi and injure the true origin; they do not know how to keep Jing-Qi sufficient nor are they skilled at timely regulation of the Shen, seeking only momentary satisfaction and immersing themselves in pleasure; their daily routines lack restraint, and thus they age before reaching fifty.

I consider that people in old age often tend toward forgetfulness because the Shen is clouded and dull; they tire after even slight activity because Qi and strength are weak. Internal cultivation (Neidan, regulating body and mind through practice) takes Shen and Qi as its foundation. When the Shen is clouded and Qi-strength is feeble, what then can serve as the root of cultivation?

The Yi says: “Water arrives clear, Xikan.” (Here the quotation means that water arrives in a clear state, and the doubled hexagram “Xikan” symbolizes successive dangers and pitfalls; the original text offers no further explanation.)

I believe that the Lingshu Jing (a classic of Chinese medicine) states: Each day the sun travels through the twenty-eight lunar mansions (the twenty-eight stellar regions delineated in ancient astronomy). The meridians of the human body number twenty-eight in all, running above and below, left and right, front and back, with a total length of sixteen zhang and two chi, corresponding to these twenty-eight mansions. Day and night are divided by the dripping of a water clock (an ancient timekeeping device) into one hundred ke.

When a person exhales once, the pulse beats twice and Qi (vital energy) travels three cun; when inhaling once, the pulse likewise beats twice and Qi also travels three cun. One full cycle of respiration moves Qi six cun; ten such cycles move it six chi. When the sun has advanced two fen, a person has taken two hundred and seventy breaths, Qi has traveled sixteen zhang and two chi, completing one circuit within the body, and the water clock has dripped two ke. When the sun has advanced twenty-five fen, the person has taken five hundred and forty breaths, Qi has completed two circuits of the body, and the water clock has dripped four ke. When the sun has advanced forty fen, the person has taken two thousand seven hundred breaths, Qi has completed ten circuits, and the water clock has dripped twenty ke. When the sun has advanced five mansions and twenty fen, the person has taken thirteen thousand five hundred breaths, Qi has completed fifty circuits, and the water clock has dripped one hundred ke. When the sun has completed its course through all twenty-eight mansions, the water in the clock has also fully drained, and the circulation of the pulse has likewise completed one full cycle. The total distance traveled is eight hundred and ten zhang.

The scripture further states: The circulation of Qi is like flowing water and also like the unceasing movement of the sun and moon. Therefore the yin meridians (the yin channels of the body) circulate through the five viscera, while the yang meridians (the yang channels) circulate through the six bowels, cycling back and forth without end; people find it difficult to know the exact period of this circulation, which proceeds in an endless cycle.

I believe that when the Qi and blood of the human body remain in constant circulation, the person is at peace; once any blockage occurs, illness arises. The way of inner cultivation (the Daoist practice of internal refinement) requires that the breath be continuous and unbroken, like a clear spring flowing steadily onward. In this manner the true Qi can pour through the body from above to below and circulate freely.

The Yijing (Classic of Changes) states: The Kan trigram represents water and also the moon; the Li trigram represents fire and also the sun.

Xiang Ping'an said that the heart takes the Kan trigram as its substance and the Li trigram as its function, and so the heart should be relaxed, empty, still, and clear. The kidneys take the Li trigram as their substance and the Kan trigram as their function, and so the Dantian (energy center) should be full and warm. Both the Sun and Yi hexagrams are composed of three yang lines and three yin lines, and their image belongs to Li. Sun symbolizes fire rising upward; Yi symbolizes fire lurking downward. Xiang Ping'an further said that when the fire which is the substance of the Li trigram surges upward, it is called “decrease”; when that same fire settles and abides below, it is called “increase.”

In my view, the method of internal refinement is extremely simple: one need only let the fire of the heart descend and enter the Dantian. The Dantian lies behind the navel and in front of the kidneys, precisely in the center of the abdomen. Practitioners of Neidan (internal alchemy) often avoid speaking of the heart and the kidneys, holding that heart and kidneys are not Kan and Li and instead calling the breath Kan and Li. In reality, the breath is merely the function of Kan and Li; the heart and the kidneys are their substance. The human body takes the heart as its sovereign, and so the heart alone occupies the center; it takes the kidneys as its foundation, and so the kidneys alone occupy the lower region. These practitioners speak not of heart and kidneys but of body and mind. Here “body” means the abdomen, and the kidneys lie within it—how then can the kidneys be overlooked?

The kidneys belong to Water and the heart to Fire. When Fire enters Water, water and fire intermingle, just as the sun and moon conjoin and their light gathers in the interval between the last day of the lunar month and the new moon. The Yijing says, “Mountain and marsh communicate their Qi (vital energy).” It also says that the two Qi of Yin-Yang respond to each other and draw into mutual affinity.

I believe that the Cantong qi says: “The operation of nature is not something produced by deviant or fabricated action; it is like the Qi (vital energy) of mountains and lakes blending with one another, rising as clouds and transforming into rain.” This means that the Yin-Yang Qi within the human body converge and condense in the Dantian (energy center, an important site in the body for refining Jing (essence) and Qi), then rise to the Niwan (the internal cultivation site in the head), where the clear Qi seems to turn into clouds and rain, moistening the entire body. A poem by Chen Xiyi (a Daoist figure) says: “Suddenly the fire-wheel stews and stirs the earth’s vessels, startling the spirit-channels so that they gush forth from the mountain peaks.” The meaning it conveys is identical.

The spirit medium recorded in the Liezi once said that the reason the Qi of mountains and lakes can communicate with each other is because of the emptiness within them. Precisely because of this emptiness, the two kinds of Qi can respond and intermingle; if there were no emptiness, they would be blocked and unable to pass through, so how could they blend with one another? The way of internal cultivation emphasizes making the heart empty and still. When the heart is empty and still, Shen (spirit) can condense and settle; when Shen is condensed and settled, Qi can gather; when Qi gathers, it will “raise clouds and become rain,” similar to the communication of Qi between mountains and lakes.

The “Far Roaming” chapter of the Li Sao says: “The Dao (the Way) can be received but cannot be transmitted; it is so small that it has no exterior, so large that it has no boundary. Do not disturb your spiritual soul, and it will operate of itself; the one Qi is vast and wondrous, nourish it at midnight; wait for it in emptiness and stillness, letting Wuwei (non-action) go first.” Zhu Ziyang (Zhu Xi) commented that what Guangchengzi (the legendary immortal) told the Yellow Emperor was nothing more than these principles; this is indeed an important secret of cultivating immortality.

The Yi says: “One opening and one closing is called change; coming and going without cease is called penetration.”

Cheng Yichuan (Cheng Yi) said that the way of cultivating body and mind lies in the incoming and outgoing of respiration; this is precisely the key to the changes of opening and closing. He also said that opening, closing, coming and going can be observed in the breath of the nose.

Zhang Hengqu (Zhang Zai) said that a person has respiration, which is the manifestation of the interaction between the two forces of hardness and softness, and also symbolizes the opening and closing of Qian and Kun (heaven and earth, Yin-Yang).

Zhu Ziyang (Zhu Xi) in his Tiaoxi Zhen (Admonition on Regulating the Breath) said: “Qi (vital energy) swirls and circulates in dense vapor; the marvels of opening and closing are inexhaustible. Who governs this transformation? In truth there is no intentional controller who manipulates it.”

I believe that the Cantong Qi (The Kinship of the Three) says: “The two functions of Yin-Yang have no fixed line positions; they circulate and operate among the six empty positions. Coming and going have no fixed measure, rising and falling follow no constant rule; they hide in the obscure and subtle, and change occurs therein.” Here the “two functions” refer to the yang line “nine” and the yin line “six,” while the “six voids” refer to the six line positions of a hexagram. The author uses this as a metaphor for the movement of one exhalation and one inhalation.

When exhaling, Qi (vital energy) issues outward—this is yang Qi opening; when inhaling, Qi enters inward—this is yin Qi closing. The Yin-Yang transformations of the human being resemble those of heaven and earth. If one can cause the breath to flow up and down, coming and going, circulating without cease, then the mysteries of opening and closing, of coming and going, are all realized within oneself. As this respiratory movement continues, the spirit gradually congeals and becomes still, the breath grows even and calm, and transformation arises from it.

Some say that from the great opening and closing of heaven and earth down to an individual’s single exhalation and inhalation, all follow the same principle: the opening and closing of one breath communicate with those of a quarter-hour, an hour, a day, a month, and a year; extended further to a lifetime, a cosmic cycle (yuan), and even the opening and closing of ten thousand ages, the principle remains the same.

The Yi (Book of Changes) says: “When the sun travels west, the moon rises; when the moon travels west, the sun rises. Sun and moon alternate in their courses, and brightness is thereby produced. When cold passes, heat arrives; when heat passes, cold arrives. Cold and heat alternate, and the year is thereby formed.”

Cheng Yi (courtesy name Yichuan) said: “The Yijing speaks of nothing more than reversal and return, coming and going, rising and falling.”

I believe that although the scriptures of the elixir masters employ extensive metaphors and winding analogies, they too speak of nothing more than reversal and return, coming and going, rising and falling. Any other interpretations are deviant and reckless practices, not the genuine principle of according with nature.

I have examined the Wenzi, which states: “Flowing water does not putrefy because it constantly moves; a door hinge is not eaten by insects because it constantly turns.” Wenzi is Ji Ran, a man of the Zhou dynasty and a disciple of Laozi. A person’s qi (vital energy) and blood likewise require circulation back and forth. Once they fail to circulate, minor cases produce illness and major cases give rise to abscesses, carbuncles, and similar ailments. Chi refers to joints that do not move freely; tan (paralysis) refers to qi and blood being congested and blocked; ju (carbuncle) refers to obstruction and lack of passage.

I have further examined the Zihuazi, which says: “Those of antiquity who understood the Dao (the Way) erected barriers to prevent the invasion of pathogenic qi and opened the sources to nourish the true qi. They dwelt in quietude, undisturbed by external things. Whether in activity or rest, in the inhalation and exhalation of breath, they were in accord with shen (spirit) and qi. They caused the hun and po souls to remain securely in their places and carefully closed the portals of the ears, eyes, mouth, and nose. With the mind concentrated and undiffused, the true qi could be preserved. The true qi poured upward and downward, the breath then circulated like flowing water and also like the sun and moon that never cease their motion. Yin qi nourished the inner viscera, yang qi secured the outer bowels; the source-stream of qi continued without interruption, abundant yet not overflowing, unimpeded yet not congested. This is called long-lasting life.” The Zihuazi was composed by Cheng Ben. Confucius once encountered him and halted his carriage to converse.

The qi and blood of the human body circulate upward and downward without pause day and night, just like the waters of rivers. People see only that river waters flow eastward into the sea, unaware that the caverns of famous mountains and great rivers communicate with one another. Why does the waterfall of Mount Lu pour down day and night without ever running dry? Because water flows beneath the earth, coming and going in circulation. The movements of the sun and moon are the same: they revolve with the celestial bodies, appearing and disappearing, coming and going without rest. If people knew that they themselves possess a sun and a moon, they would understand that this mystery of ceaseless circulation resides within their own bodies, and there is no need to seek it in distant and lofty places.

Medical texts state that the human body possesses the Ren and Du vessels. The Ren vessel originates below the Zhongji point, rises through the pubic region, proceeds upward along the inner abdomen, passes Guanyuan and reaches the throat; it is the sea of the yin vessels. The Du vessel originates at the lower pole, proceeds upward along the inner spine, enters the brain at Fengfu, then reaches the crown of the head, follows the forehead to the bridge of the nose; it is the sea of the yang vessels. The Ren is so named because women rely upon it to conceive and nourish the fetus; the Du is so named because it oversees all the meridians. When a deer turns its tail, it is said to be able to open the Du vessel; when a turtle draws in its breath through the nose, it is said to be able to open the Ren vessel. If a person can render these two vessels unobstructed, all the other meridians will likewise be unobstructed.

The Huangting Jing says: “All things operate the Heavenly Jing within the heart; preserve and guard it day and night, and one may naturally attain long life.” The Heavenly Jing is the Yellow Path within the human body, through which respiration comes and goes; what it refers to is precisely the Ren and Du vessels.

The foregoing is one juan of the Yi Wai Bie Zhuan. I have prepared diagrams and composed explanations for it, clarifying the extremely subtle principle of the circle in the Xiantian diagram, taking the Cantong Qi, the Yinfu, and similar texts as corroboration, and also drawing upon the profound views of Confucians such as Cheng Yi and Zhang Zai, thereby elaborating what Zhu Xi did not yet make clear and expanding the meanings beyond Shao Yong’s words.

Although I have not had the time to concentrate exclusively on this Dao, the marvelous efficacy of the elixir method is not something I have merely heard about; I have personally put it into practice. Therefore I dare to point directly at the essential secrets transmitted by the fangshi, in order to resolve the perplexities of students. I often lament that the elixir scriptures circulating in the world mostly employ obscure wording and secret language; readers frequently cannot find an entry, become dazed and intoxicated, and finally close the book with a long sigh. Cai Jitong and Yuan Jizhong once collated the Cantong Qi together with Zhu Xi; although they could investigate the meanings of the characters, they did not obtain accurate transmission and in the end could not escape conjecture.

Now that I have received the transmission, how could I bear to conceal it and not let others know of it? I have therefore appended this book after the Zhouyi Jishuo and entitled it Yi Wai Bie Zhuan. This means that although the theories of the elixir masters are drawn from the Yijing, they merely borrow the form of the Changes to convey their meaning and are not the original intent of the Yijing. The outline and essential points of the elixir Dao I have already set forth in full in this book; the minute oral instructions of the elixir Dao are completely recorded in the three pian of the Cantong Qi Fahui, and I shall not repeat them here.

Inscribed by Yu Yan, styled Yu Wu, the True Recluse of Stone Gorge in the Grotto-Heaven of Linwu.

The Yi Wai Bie Zhuan in one juan appearing on the right was written by my father Yu Yan and was originally appended to the Zhouyi Jishuo. My father once met a recluse who explained to him, by means of the Xiantian Tu (Prior Heaven Diagram, a schematic employed in Daoism and Yijing studies to set forth the sequential generation of Heaven and Earth), what Shaozi (Shao Yong) called “the utmost mystery at the center of the ring.” Consequently this work contains extensive elucidation of Shao Yong’s teachings.

When the Yinfu Jing Jie was recently being printed, my son Yu Zhen asked that this treatise also be copied out, collated, and issued together with it; he further included the Qinyuan Chun Jie, so that the three works form a single collection to be shared with accomplished gentlemen throughout the land. He therefore requested that the combined volume be given the overall title Xuanxue Zhengzong.

In the first month of spring of the bingshen year of the Zhizheng era (1356), the son Zhongwen, Yu Zhongwen, respectfully records this.

Here ends the Yiwai Biezhuan (A Separate Transmission Outside the Changes), in one juan.

1. According to the Siku Quanshu (Complete Library of the Four Treasuries) edition, a preface by Hao Cheng of the Qing dynasty stands before the Yiwai Biezhuan Bingshu, and after it is further appended the “Introduction to the Yiwai Biezhuan” composed by Dong Chuance of the Ming dynasty. The base text is titled “Bingshu,” yet the main body in fact contains only Yu Yan’s own preface; this is therefore specially noted here.

2. The phrase “the mind that people know” originally read “the human heart-mind”; it has been emended according to the Siku Quanshu edition.

3. “Is this not the most marvelous?” originally read “Is this not the most marvelous, the most marvelous?” The repeated words “most marvelous” are suspected to be a redundant interpolation and have now been deleted according to the Siku Quanshu edition.

4. The character “trigger” (ji) appears as “utmost” (ji) in the Siku Quanshu edition.

5. “It is the most marvelous” originally read “It is the most marvelous, the most marvelous.” The repeated words “most marvelous” have been deleted according to the Siku Quanshu edition.

6. “Language” originally read “language has.” The character “has” is suspected to be a redundant interpolation and has now been deleted according to the Siku Quanshu edition.

7. The short passage from “Qian above, Kun below” to “therefore it occupies the center” is missing from the Siku Quanshu edition.

8. At the phrase “who goes,” the Siku Quanshu edition reads “who can”; the original text that follows is defective.

9. The character “to unify” appears as “to penetrate” in the Siku Quanshu edition.

10. The term “blend and fuse” appears as “merge completely” in the Siku Quanshu edition.

11. The term “Tai and Pi” appears as “Pi and Tai” in the Siku Quanshu edition.

12. The two characters “of the Dao” were originally omitted and have been supplied from the Siku Quanshu edition.

13. The character “eye” appears as “sleep” in the Siku Quanshu edition; yet, consulting the various commentaries on the Cantong Qi (The Seal of the Unity of the Three), it should here read “to look.”

14. The character “full circuit” originally read “market” and has been corrected according to the Siku Quanshu edition.

15. “Overflow and pour out” originally read “overflow and write” and has been corrected according to the Siku Quanshu edition.

16. The term “full and vigorous” appears as “vigorous and full” in the Siku Quanshu edition.

17. “The face withered” originally read “turned and withered” and has been corrected according to the Siku Quanshu edition.

18. The term “grizzled hair” appears as “white beard” in the Siku Quanshu edition.

19. The text from “The foregoing is the Yiwai Biezhuan, one juan” to “Zhongwen bows a hundred times and respectfully records this” was originally inserted in the middle of the main text of the Yiwai Biezhuan in the base edition, and was accompanied by a rhapsody titled “Rhapsody on the Gate of the Mysterious Female.” This is suspected to be a misplacement, and the position has now been adjusted according to the Siku Quanshu edition.

20. The character “one who” has been supplied from the Siku Quanshu edition.

21. The term “hidden phrasing” appears as “mansion phrasing” in the Siku Quanshu edition.

22. The character “then” likewise appears as “then” in the Siku Quanshu edition.

23. The several sentences from “the great outline and essential principles of the alchemical Dao” to “written by Yu Dan, the old man of Yuwu” are abbreviated in the Siku Quanshu edition as: “The details are recorded in the three chapters of the Elaboration of the Cantong Qi, and will not be repeated here. Written by Yu Yan of Shijian.”