《易外别传》

Yiwai Biezhuan is a single-volume work by Yu Yan of the Yuan dynasty. Drawing on Shao Yong’s Earlier-Heaven diagram, a system of hexagram images used to explain the principles of the Yijing, it sets out the aims of Daoist Neidan (internal alchemy).

The Earlier-Heaven diagram is traditionally said to have originated with Chen Tuan. From the Southern Song onward, most people regarded it as a diagram secretly handed down by Fuxi and believed it revealed the original meaning of the hexagrams and their lines. Lin Li, a disciple of Zhu Xi, criticized this view with reasoned arguments, but few agreed with him at the time, and no forceful rebuttal took shape. During the Yanyou era of the Yuan dynasty, Chen Yingrun of Tiantai pointed out that the Earlier-Heaven diagram was in fact about the furnace and fire of alchemical refinement described in the Cantong qi. His argument had a sound basis, but those who revered the Yellow River Diagram and the Luo River Writing were deeply reluctant to discuss the matter, and their arguments grew tangled.

When Yu Yan wrote this book, he made no effort to conceal his views. In the postface, he explained that the title Yiwai Biezhuan means that although alchemists borrow the language of the Yijing, they merely imitate and allude to it; their teachings are not the original meaning of the Yijing. The bibliographic note takes this as evidence that Yu Yan could clearly distinguish right from wrong and was unwilling to go against his honest judgment.

The postface says that the book was originally appended to the Collected Explanations of the Zhouyi, and Yu Yan’s son Zhongwen records the same in his colophon. According to its preface, the Tongzhitang edition of the Collected Explanations of the Zhouyi once included two additional works, Essentials of the Yijing Diagrams and Yiwai Biezhuan. Yet surviving printed copies do not contain Yiwai Biezhuan. The bibliographic note suggests that after the printing blocks were first cut, the editors may have decided the work did not belong with the Collected Explanations of the Zhouyi and removed it.

Bai Yunji’s Catalogue of the Daoist Canon lists Yiwai Biezhuan alongside Yitong Tongbian and Yishi Tongbian in the Taixuan section, attributing all three to Lei Siqi. But neither of the prefaces written for Lei Siqi by Jie Xisi and Wu Quanjie mentions this book. The bibliographic note therefore suspects that Bai Yunji may have mistakenly attributed all three works to Lei Siqi simply because they had once been bound in the same case.

The one-volume Additional Writings on the Changes was written by Yu Yan in the Yuan dynasty. It originally had prefaces at both the beginning and the end. The Gazetteer of Suzhou Prefecture records that Yu Yan, whose courtesy name was Yu Wu, was from Linwu Mountain in Wu County. Born during the Baoyou era of the Southern Song, he became known for his poetry and prose. After the Song fell, he withdrew from public life and devoted himself to writing. He was deeply learned in the study of the Changes and also enjoyed playing the qin. In his later years he called himself Stone Stream, and he died during the Yuanzhen era at about seventy years of age. His writings on the Changes, in more than a hundred volumes, were titled Collected Essentials of the Great Changes. He also wrote commentaries on the Upper and Lower Classics of the Book of Changes and the Ten Wings, in forty volumes, titled Collected Explanations of the Book of Changes. Only the Collected Explanations has survived. Cheng included it in the Tongzhitang Collection of Classical Commentaries, together with two works, Essentials of the Diagrams of the Changes and Additional Writings on the Changes.

In an afterword, Yu Yan’s son Zhongwen wrote that Additional Writings on the Changes was his father’s work and had been appended to the Collected Explanations of the Book of Changes. His father had once met a recluse who instructed him using the Prior-Heaven Diagram, a diagram that represents the sequence in which Heaven and Earth arise through the transformations of Yin and Yang. This helped him grasp the most profound principles of Shao’s teachings. Accordingly, the book largely expounds Shao’s learning. Zhongwen’s afterword has since been lost. Wu Cheng Songli Xiaoyin, drawing on the Jingyi kao, wrote this account on the sixteenth day of the sixth month of the bingxu year of the Qianlong reign, at the Studio of Flower Vases, when he was sixty-five.

What is called Additional Writings on the Changes discusses the mystery of the “center of the ring” in the Prior-Heaven Diagram—the pivot of the cyclical transformations of Yin and Yang—and is also related to the teachings of Wei Boyang’s Han dynasty Cantong qi. Human beings live between Heaven and Earth: the head belongs to Qian, and the abdomen to Kun. Breathing corresponds to the sun and moon, so the human body undergoes the same Yin-Yang transformations as Heaven and Earth. The Changes explains the Way of Yin and Yang; Wei Boyang drew on the Changes to illuminate his teachings, whose essential meaning is largely contained in the Prior-Heaven Diagram. Though this is only one part of the study of the Changes, it is also important knowledge for a cultivated person seeking to nourish life.

The wondrous quality of the Prior-Heaven Diagram lies in its passage from the Kun hexagram to the Fu hexagram, then in its ceaseless return through the cycle. Its subtlest point lies in the transition between Kun and Fu, as movement and stillness alternate. I once studied this teaching and read the Daoist collection Seven Tablets in a Cloudy Satchel from beginning to end, gaining a slight understanding of it. Later, by chance, I met a recluse who taught me how to read the Changes. Only then did I fully understand the mystery of the “center of the ring.” Looking back at myself, I saw that the Taiji, the root of Heaven and the cavern of the moon, and the thirty-six palaces described by Shao Kangjie could all be found within the human body. This is what is called “the Changes within the body.”

I have now drawn the diagrams below and added explanations by earlier Confucian scholars, setting out the principles clearly. Readers will understand at a glance; those who truly grasp the teaching will naturally gain insight. Written on the fifteenth day of the eighth month of the jiashen year of the Zhiyuan era, by Yu Yan, Daoist of Stone Stream, of Ancient Wu.

Preface and Postscript, with Table of Contents, to A Separate Transmission Beyond the Changes

This book was written by the Yuan dynasty Confucian scholar Yu Yan, also known by the literary name Shijian. It includes discussions by Confucian scholars of earlier generations. Its content is clear and easy to understand, so readers can grasp it at a glance. On the fifteenth day of the eighth month of the Jia Shen year of the Zhiyuan era (1284), Yu Yan, the Daoist of Shijian in ancient Wu, wrote this preface.

This book was written by the Yuan dynasty Confucian scholar Yu Yan and was once printed at the Jisi, an ancient government office, by Mr. Huang Houfeng in the Ming dynasty. While observing a quiet retreat around the Winter Solstice, I found the book and read it. Many of its statements seem ordinary, but their meaning is profound. For example, “At the meeting of Kun and Fu, when stillness reaches its utmost, the subtle impulse stirs” means that when Yin stillness reaches its limit, the living impulse of Yang movement begins to emerge. “Hide the heart in the abyss; Qi and Shen unite” means that the heart and spirit settle into deep stillness, and Qi joins with Shen. “Mysteriously joined and condensed, they circulate without ceasing” describes a subtle fusion and condensation that continues in motion. “Maintain fullness and govern Shen; true Qi continues without interruption” means preserving a state of fullness and directing it with the mind’s intent, so that true Qi flows on without end. These words reveal the secrets of the prenatal pivot, where Yin and Yang have not yet divided and the movement of Qi turns. The Daoist terms “medicinal substances” and “fire timing”—names in internal alchemy for the vital substances and the rhythms of cultivation—are all contained within them. Though the book often explains its teachings through the human body, the workings of Heaven and Earth can also be inferred by moving from what is near to what is far.

I have often wondered why those who cultivate health, longing for longevity and giving free rein to their desires, so often stray into heterodox paths without realizing that this book offers instructions for sweeping away false teachings and returning to the right path. It is called A Separate Transmission Beyond the Changes, yet in truth it supplements and illuminates the Classic of Changes. Mr. Huang had his own purpose in printing and preserving it. In the past, I traveled ten thousand li and practiced stillness for many years. Only later, when an accomplished teacher instructed me in person, did I grasp the subtle moment when Yang Qi begins to arise. I also came to understand that the true principle governing body and mind is set in motion from within, and that its growth has its own timing. Yet I still regret that I cannot fully rein in my temperament: at times I let things go unchecked, and at others I deliberately try to force their growth. I have not yet reached the state of responding freely and suddenly understanding their subtle workings. Now that I have obtained this book, it can serve to confirm what I have learned, and I am deeply grateful. I have therefore written this preface, corrected the text, and printed several copies to give to like-minded people for safekeeping. Those who read this book as it circulates in the world should not be confined by its diagrams of the hexagrams, nor fixate on what is called “the midpoint of Zi and Wu”—the pivotal position where Yin and Yang Qi shift, represented by the Zi and Wu branches. Simply clear the mind and spirit and nourish the breath; understanding will come naturally. Is this not also a true seed of our Dao? Written at the Winter Solstice in the Xin Wei year of the Longqing era (1571) by the Layman Who Embraces Unity, Dong Chuance.

The Separate Transmission Beyond the Changes included in the Imperially Commissioned Complete Library of the Four Treasuries was written by the Yuan dynasty author Yu Yan. Its contents include: Diagram of the Heart as the Taiji (Supreme Ultimate); Diagram of the Prenatal Roots of Heaven and Moon Caves; Diagram of the Prenatal Sixty-Four Hexagrams in Vertical Sequence; Diagram of Earth Receiving Heaven’s Qi; Diagram of the Moon Receiving the Sun’s Light; Diagram of Qian above Kun in the Prenatal Arrangement and Li in the South and Kan in the North in the Postnatal Arrangement; Diagram of Qian, Kun, Kan, and Li Matched with Heaven, Earth, Sun, and Moon; Diagram of Eight, Seven, Nine, and Six Matched with Wood, Fire, Metal, and Water; Diagram of the Twelve Hexagrams Transformed through the Interaction of Qian and Kun; Diagram of the Twelve Hexagrams Transformed through the Interaction of Kan and Li; Diagram of the Ascent and Descent of Hexagrams in Reversed and Opposed Pairs; and Diagram of the Fire Timing in the Cantong qi.

In the Xiantian diagram, a scheme that represents the workings of Heaven and Earth through the changes of Yin-Yang and the sequence of the Eight Trigrams, the Cantong qi says: “It ends with Kun and begins with Fu, like a circular cycle without end.”

Shao Kangjie, a Northern Song scholar of the Yijing, wrote: “Since I grasped the principle of the center of the circle, every distracting thought in my mind has vanished.” He also said: “When Qian meets Xun, one can observe the Moon Grotto; where the earth meets the thunder of Zhen, one can see the Celestial Root. The Celestial Root and the Moon Grotto move back and forth between one another; all thirty-six palaces are filled with spring.”

I believe the Moon Grotto is above and the Celestial Root below; what moves back and forth between them is the mind. The “thirty-six palaces” refer to the sequence of the Eight Trigrams: Qian is first, Dui second, Li third, Zhen fourth, Xun fifth, Kan sixth, Gen seventh, and Kun eighth. To say that “all thirty-six palaces are filled with spring” means that a harmonious, flowing Qi circulates throughout the body. Seen this way, the thirty-six palaces are not only in the diagram on paper; they are also within our bodies. Shao Kangjie understood this principle, as did Zhu Ziyang (Zhu Xi, a Southern Song Neo-Confucian scholar), but ordinary Confucian scholars did not.

In his Huangji Jingshi, Shao Kangjie says: “The Xiantian diagram is the center of the circle.”

I believe the human body itself is the Xiantian diagram. The mind lies at the center of the body, just as Taiji lies at the center of the Xiantian diagram. This is what Zhu Ziyang meant by “the empty space in the middle.” The diagram begins with Fu and ends with Kun, its beginning and end joined like a ring; hence it is called a “ring.” The “center of the ring” is where Taiji sits, with the sixty-four hexagrams arranged around it. The Yijing calls this Taiji; in the human body, it corresponds to the mind. Once a person understands that the mind is Taiji, it becomes possible to speak of the Dao.

It is also said: after the winter solstice comes exhalation, and after the summer solstice comes inhalation. These are the breaths of Heaven and Earth over the course of the year.

Zhu Xi said that between Heaven and Earth there is only one Qi (vital energy) in circulation. The span from this year’s winter solstice to next year’s winter solstice is like a single breath: exhaling belongs to Yang, and inhaling belongs to Yin. I understand that after the winter solstice, the change from the Return hexagram to the Qian hexagram belongs to Yang, so it is compared to “exhaling”; after the summer solstice, the change from the Gou hexagram to the Kun hexagram belongs to Yin, so it is compared to “inhaling.” Exhaling is Qi moving outward, so it corresponds to the period after the winter solstice; inhaling is Qi moving inward, so it corresponds to the period after the summer solstice. The movement of Heaven and Earth over a full year is like one great breath, while each inhalation and exhalation in the human body is like one small breath. The Cantong qi says, “The dragon exhales toward the tiger; the tiger inhales the dragon’s essence,” and also, “Exhalation and inhalation contain and nurture one another; stillness and breath become husband and wife.” Here, breathing is likened to dragons and tigers, and to husband and wife. Although the various classics and commentaries use many metaphors, in the end they say no more than “exhalation and inhalation.”

It also asks: “Is the alternation of movement and stillness the most subtle matter between Heaven and Earth? Is the transition between movement and stillness the most subtle matter among Heaven, Earth, humanity, and the myriad things?”

Zhu Xi said that the left side of the diagram belongs to Yang and the right side to Yin. I understand that the left side, from the Return hexagram to the Qian hexagram, represents Yang Qi stirring into motion, while the right side, from the Gou hexagram to the Kun hexagram, represents Yin Qi settling into stillness. The transition between movement and stillness occurs when the Kun hexagram is nearing its end and the Return hexagram is just beginning to emerge—that is, when Yin and Yang meet. In the year, this corresponds to the winter solstice; in the month, to the transition between the last and first days of the lunar month; and in the day, to the end of the Hai hour and the beginning of the Zi hour. Meng Kang said that the west of the Zi hour and the east of the Hai hour mark this boundary. I understand that the moment when Qian and Kun meet within the human body likewise corresponds to the winter solstice of the year, the transition between the last and first days of the lunar month, and the end of Hai and beginning of Zi in the day. The west of Zi and east of Hai mentioned by Meng Kang also refer to this boundary. I understand that when Qian and Kun meet within the human body, stillness reaches its utmost point and the moment for movement appears, corresponding to the culmination of Heaven and Earth’s cycles. This truly is the most subtle matter among Heaven, Earth, humanity, and the myriad things.

It also says: “‘Silent and unmoving’ means that there is no Yang Qi, like the image of the Kun hexagram; ‘when stimulated, it then penetrates the workings of all things under Heaven’ means that Yang Qi stirs into motion within, as expressed by the Return hexagram.”

I understand “silent” as stillness brought to its utmost point, that is, the purely Yin Kun; “stimulated” as the beginning of movement, that is, the Return hexagram in which Yang Qi first emerges. Between silence and stimulation lies the threshold where movement and stillness alternate.

It also says that before the Non-Ultimate becomes manifest, Yin contains Yang; once form appears, Yang Qi divides and gives rise to Yin.

Zhu Ziyang (Zhu Xi) said that Shaozi (Shao Yong) explained the principles of Yin-Yang’s cyclical transformations through the diagrams of the Yijing. From the Gou hexagram to the Kun hexagram, Yang is contained within Yin; from the Fu hexagram to the Qian hexagram, Yin differentiates out of Yang. The interval between the Kun and Fu hexagrams is precisely where Non-Polarity and Taiji meet and transformation begins.

Zhongji said that Zhu Xi’s view that the interval between Kun and Fu is Non-Polarity is exceptionally perceptive. Zhu Xi also wrote: “Suddenly, at midnight, a clap of thunder; a thousand households and ten thousand gates open one after another. If you know that forms are contained within the formless, you may see Fuxi himself.” “Forms are contained within the formless” refers to the state between Kun and Fu, where Non-Polarity and Taiji are one. Who could have clarified Shaozi’s learning if not Zhu Xi?

In his “Song on the Winter Solstice,” Shaozi wrote: “The winter solstice falls at the midpoint of the Zi hour; Heaven’s heart has not changed. Yang Qi has only just stirred, and the myriad things are not yet born. The dark liquor used in ritual has a faint taste; the greatest sound between Heaven and Earth is scarcely audible. If you do not believe these words, ask Fuxi again.” Here, “dark liquor” refers to the clear water used in ancient sacrifices, while “great sound” means the immense sound of Heaven and Earth, too faint for the ear to hear.

He also wrote: “What is meant by ‘incipience’? The principle of Heaven’s root is exceedingly subtle. The moment when this year draws to a close is also the moment when tomorrow begins. It is easy to sense the meaning of this instant, yet difficult to put it into words. If one can understand this principle, what is there that one cannot understand?” “Heaven’s root” refers to the source from which Yin and Yang generate and transform; “incipience” means the subtle first signs of change, before they become apparent.

He also wrote a poem in response to Professor Wei’s poem: “Whenever I read until I reach Heaven’s root, I worry that you will ask about the most profound principles.”

Zhu Ziyang said that “the midpoint of the Zi hour” refers to the very beginning of that hour, before it has fully arrived—the transition from the Hai hour to the Zi hour. He also said that the place where Yang Qi first stirs lies at the transition between Zheng and Yuan. The author considers this the true subtle mechanism through which creation operates. Cheng Yichuan (Cheng Yi) said, “If one has not glimpsed the subtle workings of creation, how can one attain longevity?” These are profound words.

In his “Song of the Misty and Elusive,” Shaozi wrote: “Yin and Yang begin to change amid the misty and elusive; the Qi of Heaven and Earth has just begun to mingle, condense, and circulate. How could that single wondrous scene be expressed through words or practice?”

The author believes that this poem by Kangjie (Shao Yong) reveals the most profound principles of Heaven’s root. Unless one has personally entered the misty and elusive state and truly experienced the mingling and union of the Qi of Heaven and Earth, how could one know its mysteries?

Shao Kangjie’s Book of Supreme Principles Governing the World says, “Perhaps the foundation of Heaven and Earth begins with the ‘center.’ Thus, although Qian and Kun—the Heaven and Earth trigrams in the Changes—undergo repeated transformations, they never depart from this center.”

The book also says, “Movement from below upward is called ascent; movement from above downward is called descent. Ascent signifies growth, and descent signifies decline. Thus Yang Qi arises from below and Yin Qi arises from above, and all things, through transformation, return to their roots and are reborn.” It also says, “Yang is born within Yin, and Yin is born within Yang; Yin gives rise to Yang again, and Yang gives rise to Yin again. So the cycle repeats without end.”

The “Ode to Qian and Kun” says, “The Dao is not far from people; Qian and Kun are within the human body. Why seek Qian and Kun somewhere beyond Heaven and Earth?”

In my view, Qian and Kun represent pure Yin and Yang, while Kan and Li—the Water and Fire trigrams in the Changes—represent the union of Yin and Yang. The Qian trigram is pure Yang and symbolizes Heaven, so it lies above the central position. The Kun trigram is pure Yin and symbolizes Earth, so it lies below the center. Kan contains Yang within Yin and symbolizes the moon; Li contains Yin within Yang and symbolizes the sun. The sun and moon therefore lie between Qian and Kun.

The transformations of the other sixty-four hexagrams begin with a single Yang line emerging from Kun. Yang gradually increases until there are five Yang lines, at which point its Qi has risen to its utmost. The next transformation produces Qian, with all six Yang lines complete. Conversely, a single Yin line emerges from Qian and gradually increases until there are five Yin lines, at which point Yin Qi has descended to its utmost. The next transformation produces Kun, with all six Yin lines complete. Ascent and descent, movement between above and below: the cycle continues without end.

Heaven and Earth work in this way, and so does the human body. At the Zi hour (midnight), Qi moves to the weilü, the area at the base of the spine. During the Chou and Yin hours, it is at the waist; during the Mao, Chen, and Si hours, it is along the back; at the Wu hour, it reaches the niwan, the upper Dantian in the head. During the Wei, Shen, and You hours, it is in the chest and diaphragm; during the Xu and Hai hours, it returns to the abdomen. This is the daily cycle of Qi’s ascent and descent. Breathing works in the same way: when one inhales, Qi rises from below; when one exhales, Qi descends from above.

In Heaven, this movement corresponds to the stars, as though the Big Dipper’s handle points toward the Zi and Wu directions. On Earth, it corresponds to the tides and their changes when the moon moves toward the Zi and Wu directions. Zi and Wu are the central positions in the movements of Heaven and Earth. The Cantong qi, a Daoist alchemical classic, says, “Conforming to the tally, it moves through the center,” and “Its movement and transformation never depart from the center.” It also says one should “drift freely while keeping to the circle’s center.” If a person can recognize the center within themselves and bring it into accord with the center of Heaven and Earth, then Qian and Kun are not only between Heaven and Earth; they are within oneself as well. Where can I find someone who understands the Dao of transformation, so that I may speak with them about Qian and Kun within the body and investigate more deeply this center within us? Ah!

The Classic of Changes says, “How great is Kun Yuan, the generative power of Earth! All things depend on it to grow, and it follows the Way of Heaven.”

The Cantong qi (a Daoist alchemical classic) says, “Constantly follow the patterns of Earth, receiving the Way of Heaven and setting it into motion.” I believe that a person’s original Qi is stored in the abdomen, just as all things are stored in the Earth. Shen sinks into the Dantian, just as the qi of Heaven descends to the ground. When Qi and Shen unite, it is like Earth receiving the Way of Heaven. Heaven and Earth give birth to all things through this mutual correspondence; in the same way, we refine the medicine within ourselves. The Taixuan jing says, “When the heart is stored in the stillness of an abyss, the spiritual root grows more beautiful.” This expresses the same idea.

Shao Yong said, “The moon is dark in itself; it appears bright by receiving the sun’s light.” I believe the sun belongs to Yang and the moon to Yin. The moon has no light of its own; its light comes from the sun. Yang is bright and Yin is dark; Yang actively gives, while Yin receives and accepts. Thus, Greater Yin (the Yin aspect of Qi) receives the sun’s light and becomes bright. The human heart is like the sun, and the sea of Qi (the place where original Qi gathers) is like the moon. When the heart is settled, Shen gathers; when Shen gathers, Qi accumulates. If a person can concentrate Shen and sink it into Qi, then Qi and Shen unite, just as Greater Yin receives the sun’s light.

Shao Kangjie says: “Shen (spirit) is rooted in the heart, Qi (vital energy) is governed by the kidneys, and the body is governed by the head. Form and Qi interact, while Shen resides among them and takes the leading role. This is the Way of the Three Powers: Heaven, Earth, and Humanity.”

I believe the human body can be compared to Heaven and Earth: the head belongs to Qian, the abdomen to Kun, and the heart lies between them, just as each of the Three Powers has its proper place. Qi is governed by the kidneys, and form by the head; one is above and the other below, and by themselves they do not meet. Shen brings them together. Moving between them, Shen allows above and below to merge into one and flow in harmony with Heaven and Earth. Is this not the Way of the Three Powers?

When Shen remains in the kidneys, it is still and settled, hidden within. This is the Way of Kun. When Shen remains in the head, it is active and in motion. This is the Way of Qian. In concealment, the subtle essences of Yin and Yang unite and gather; in motion, they circulate without end. The state of union and gathering is called the “medicine,” while this ceaseless circulation is called the “fire.” The Yinfu Jing says, “The pivot lies in the eyes,” meaning that the key lies in the eyes.

Shao Kangjie also says: “The spirit of Heaven appears in the sun; the spirit of the human being appears in the eyes.”

I believe that wherever the gaze falls, the mind and Shen follow. Therefore, the method of internal cultivation is to look at the tip of the nose, then align the nose with the navel, allowing the heart’s fire to descend to the Sea of Qi, the Dantian region below the navel. The whole process takes only a brief moment.

The Changes says that Qian represents Heaven, Kun represents Earth, Li represents the sun, and Kan represents the moon. It also says that Qian represents the head and Kun the abdomen.

The Scripture of Great Mystery says that Yang Qi quietly begins to sprout within the Yellow Palace. The Scripture of the Yellow Court says that to seek long life and freedom from death, one must cultivate Kunlun. It also says to preserve the breath as the sun and moon rise, set, and move through their cycles.

I believe the head is at the upper part of the body, round in shape, and where the Yang Qi gathers. It thus resembles the image of Heaven, which is why the Changes uses Qian to represent the head. The Scripture of the Yellow Court speaks of cultivating Kunlun because Kunlun lies to the northwest, corresponding to the Qian position. The abdomen lies below the body, centrally placed and hollow within; it is where the Eight Vessels converge. It thus resembles the image of Earth, which is why the Changes uses Kun to represent the abdomen. The sky is dark and mysterious, while the earth is yellow; therefore, the Scripture of Great Mystery identifies Kun with the Yellow Palace. The sun rises in the east and the moon in the west, which is why the Changes uses Li to represent the sun and Kan to represent the moon. Breath flows in and out, with the breath rising and falling in a continuous cycle; for this reason, the Scripture of the Yellow Court uses breathing as a metaphor for the movement of the sun and moon. Some compare the two eyes to the sun and moon, but this is mistaken: the eyes have only the sun’s and moon’s shapes, not their function of moving through cycles.

The Cantong qi says, “Nine returns, seven reverses, eight comes home, and six abides.” It also says, “Seven joined with eight makes fifteen; nine and six likewise correspond.” It further says, “Where Metal and Water unite, Wood and Fire become companions; the four mingle and take their places as the Dragon and Tiger.”

I believe six, seven, eight, and nine are the completed numbers of Water, Fire, Wood, and Metal: Wood’s number is eight and it belongs to the east; Fire’s number is seven and it belongs to the south. Wood rises from the east and, upon reaching the south, becomes Fire’s companion. Metal’s number is nine and it belongs to the west; Water’s number is six and it belongs to the north. Metal descends from the west and, upon reaching the north, unites with Water.

The “Red Dragon” and “Black Tiger” spoken of by Neidan practitioners are also metaphors. When the seven lodges of the Azure Dragon in the east move to the south, it is called the Red Dragon; when the seven lodges of the White Tiger in the west move to the north, it is called the Black Tiger. These expressions are all metaphors for the breath within the body. Ultimately, where are there really any Dragons and Tigers, Metal and Water, Wood and Fire, or seven, eight, nine, and six? They are all just metaphors.

Some may wonder: Why are nine, seven, and eight said to “return,” “reverse,” and “come home,” while six alone is said to “abide”? Does this indicate a difference? The answer is that six abides in the north and does not move. The returns, reversals, and homecomings of the other three directions ultimately converge in the north; hence the word “abide.”

Qian above and Kun below refer to Heaven and Earth within my body. The Tai hexagram on the left and the Pi hexagram on the right refer to the rising and descending of Heaven-and-Earth Qi within my body. The “Zi” in the Fu hexagram does not mean the eleventh month of the calendar or the Zi hour at midnight; it means the Zi within the body. The “Wu” in the Gou hexagram does not mean the fifth month or the Wu hour at noon; it means the Wu within the body. Zhang Wuzhen says, “When Pi and Tai join, Yin and Yang rise and descend.” He is speaking of the changes of Pi and Tai within the body.

Kan in the north and Li in the south refer to Water and Fire within my body. The Ji Ji hexagram in the east and the Wei Ji hexagram in the west refer to the rising and descending of Water-and-Fire Qi within my body. The Tun hexagram occupies the Yin position, and the Meng hexagram the Xu position; this refers to the changes in the firing process within my body. Yin here does not mean the Yin hour in the early morning, nor does Xu mean the Xu hour at dusk; they are the Yin and Xu within the body. Zhang Wuzhen says, “Tun and Meng symbolize movement and stillness; Pi and Tai symbolize…”

Kan (Water) is in the north and Li (Fire) in the south; this refers to Water and Fire within the human body. The hexagram Ji Ji is in the east and Wei Ji in the west; this refers to the way Water and Fire rise, descend, and circulate within the body. The Tun hexagram corresponds to the Yin hour, and the Meng hexagram to the Xu hour; this refers to the timing and degree of refinement during cultivation within the body. Yin here does not mean early morning, nor does Xu mean dusk: they refer to Yin and Xu within the body. Zhang Wuzhen said, “Tun and Meng speak of movement and stillness, that is, morning and dusk.” He was speaking precisely of Tun and Meng within the body.

The Cantong qi says: “On the new moon, the Tun hexagram takes charge; by evening, the Meng hexagram succeeds it. One hexagram is used for day and one for night, proceeding in sequence. When Ji Ji and Wei Ji are reached, dawn is about to break and the cycle ends, then begins again at once. Taking the days and hours as a cycle, movement and stillness each have their appointed times: in spring and summer, emphasis is placed on inner operation, from the Zi hour through the Chen and Si hours; in autumn and winter, emphasis is placed on outer operation, from the Wu hour through the Xu and Hai hours.”

In my view, the Cantong qi takes Qian and Kun as the cauldron—the vessel for refining the elixir—and Kan and Li as the ingredients, while the other sixty hexagrams represent the firing phases. A day has twelve double-hours, and two hexagrams together have twelve lines; hence two hexagrams are used each day. Tun is used in the morning and Meng in the evening; Xu in the morning and Song in the evening, and so on in sequence until Ji Ji and Wei Ji. Turn Tun upside down and it becomes Meng, symbolizing ascent and descent: Tun rises upward from within, representing morning, daytime, spring, and summer; Meng descends from without, representing evening, nighttime, autumn, and winter. The other hexagrams follow the same pattern.

Assigning the sixty hexagrams to thirty days symbolizes a month. What if it is a short month of only twenty-nine days? This is simply an analogy; cultivation is not actually to be carried out according to a thirty-day schedule. Some take these explanations as a method of closing the eyes and counting breaths. That would be tedious and exhausting—how could it be a teaching of utmost simplicity and ease?

The Diagram of the Cauldron, Vessel, Ingredients, and Firing Phases of the Golden Elixir: The Many Manifestations Arising from One Source in the Zhouyi Cantong qi says: “This subtle art is examined with care and explained in full; it contains no deception. It is passed down to countless millions in later generations. Its clarity can be verified: it shines brilliantly like the star charts of the Han dynasty and is as evident as rivers flowing into the sea. Reflect on it and become thoroughly familiar with it; investigate it repeatedly, moving up and down a thousand times, and its principles will become clear. Read it ten thousand times, and perhaps you will glimpse its mysteries. The spirits may offer people guidance, allowing the mind to understand suddenly. Search for the source and trace the pathways, and you will surely find a way to enter. The Way of Heaven shows no partiality; it often transmits the Dao to the worthy.”

The above is the “Nine-Ring” diagram, made with slight additions and omissions after correcting Peng Zhenyi’s Diagram of the Bright Mirror.

The Zhouyi says: “The movement of Heaven is vigorous and unceasing; the noble person should strive constantly to strengthen themselves.”

Hu Anding says: When we look up at the sky from the ground, we see its deep blue-green color. The South Pole lies thirty-six degrees below the horizon, while the North Pole rises thirty-six degrees above it. The sky’s shape is like a pestle leaning at an angle: this is the form of the celestial sphere. In terms of its movement, the sky travels more than nine hundred thousand li in a single day and night. A person’s single breath is called one respiration; in that span, the sky has already traveled more than eighty li. By the end of one day and night, it has traveled more than nine hundred thousand li. From this we can understand the sky’s vigorous, unceasing motion.

He also says: When a person’s spirit and vital energy gather, they can live; when they disperse, the person dies. The sky possesses the firm, Yang energy of strength and brightness, and moves without ceasing. That is why the celestial sphere can endure.

I believe that the Cantong qi (Token for Joining the Three, a Daoist classic on the changes of Yin-Yang and cultivation) says, “The pivot has its high and low points, and so the circuit of heaven turns.” Here, “pivot” refers to the North and South Poles, “circuit of heaven” to the twenty-eight lunar lodges—the twenty-eight regions into which the ancients divided the sky—and “turns” to their motion. The celestial sphere rotates in cycles like a pellet, without pause by day or night. Its northern and southern ends, one high and the other low, are what is meant by the “pivot.”

The human body follows a similar principle: above is the Celestial Pass, and below is the Earthly Axis. If one can make the Celestial Pass revolve and the Earthly Axis turn, the breath can move between above and below, completing one circuit of heaven with each respiration.

I also believe that the Cantong qi says, “Move along the Jade Pivot, ascending and descending.” The Jade Pivot refers to the Northern Dipper, and can also mean the hub of the celestial motion. The sky takes the Northern Dipper as its hub; the human being takes the heart as the hub. The heart’s movement within the body is like the Northern Dipper’s movement in the sky.

The Yinfu jing (Scripture of the Hidden Accord), a Daoist classic, says, “Observe the Way of Heaven and grasp the patterns of its movement; that is enough.” This means that the human way and the Way of Heaven are connected. If a person draws in the gaze, turns hearing inward, and observes within, letting the heart grow still and settle deep, while regulating the breath’s coming and going so that it circulates without pause, then they can move in accord with the Way of Heaven and grasp the hub of its motion. Yet the Way of Heaven can be observed, while mastering the sky’s movement is difficult; only those who are open and humble can do so.

The Changes says: “When a gentleman’s inner life is full and accords with what is right, he stands properly in his rightful place and keeps to his own duty. Virtue is held within, revealed in the bearing of the limbs, and put into practice through one’s work. This is virtue brought to its fullest expression.”

Xu Jinzhai says: Practitioners of the Elixir Arts (Daoist Neidan cultivators) also drew on this idea. The Cantong qi (a Daoist alchemical classic) says: “The Yellow Center gradually comes to understand what is right; nourishing Qi reaches the skin.” Yet the two passages have different aims. The Changes speaks here of moral cultivation, holding that virtue comes from the Way of Heaven and can be experienced by everyone. The Cantong qi, by contrast, speaks of nourishing the body’s Qi and blood and putting the effects of cultivation into practice within oneself.

I believe the Cantong qi simply borrows the principles of the Changes to explain its own teachings. When it quotes words from the Changes, it does not necessarily retain their original meaning. The Changes resembles Heaven and Earth, and the human body likewise resembles Heaven and Earth. For this reason, Wei Boyang drew on the Changes when writing the Cantong qi. Here, “Yellow Center” refers to the “Yellow Path” within the human body, through which he expresses his own ideas about cultivation.

The Changes says: “After a mistake, if one turns back in time, regret is not far away. This is greatly auspicious.”

Zhu Ziyang says: Laozi taught that the best way to manage human affairs and follow the Way of Heaven is to practice “cherishing”—that is, to treasure and conserve the Qi of body and mind. To cherish it is called “taking it up early.” By gathering in and settling body and mind early, one can keep accumulating virtue. Laozi explains this principle clearly: “taking it up early” means caring for oneself while the loss is still small, so that one does not stray far from the right path; “accumulating virtue greatly” means adding to what has already been accumulated through cherishing and care.

The same applies to caring for the body: exercising restraint and tending to it before it is harmed is called early care and continued accumulation. If one waits until the body has already been depleted before tending to it, care can only restore what has been lost; it cannot count as continued accumulation. The key, then, is to recognize early on, while the body has suffered no marked loss, that one should cherish it.

Zhu Ziyang also lamented: “My body is already weak, like a dilapidated house, propped up on one side while the other is caving in. Even if I wished to cultivate myself, there would be little benefit left to gain. This year I received a letter from Cai Jitong and learned that he has recently come to understand the principles of nourishing life deeply and has mastered its methods. But my own body is already like a city wall and house that have fallen into disrepair. Even if I know the methods, it is difficult to put them to good use. I suppose that is simply how things are.”

When I consulted the Youji Xian Zhuan, I read that Zhou Cong was from Sizhou. Xu Shenweng thought highly of him and said, “I married when I was young, but this man attained the Dao at a very early age. His spirit is complete; I cannot compare with him.” Someone like Zhou Cong must be what Laozi meant by “early on taking up and practicing the Great Dao, and continually accumulating De.”

I also consulted the Suwen. It says that a man’s body changes every eight years. At sixteen, his Kidney Qi is flourishing, and tiangui—the vital essence that brings reproductive functions to maturity—arrives. His essence is abundant and Yin-Yang is in harmony, so he can father children. At twenty-four, his Kidney Qi is balanced, his sinews and bones are strong, his wisdom teeth have grown in, and his physical development reaches its peak. At thirty-two, his sinews and bones are robust and his muscles full. At forty, his Kidney Qi begins to decline; his hair falls out and his teeth become brittle. At forty-eight, the Yang Qi in his upper body weakens, his complexion becomes haggard, and his hair and beard begin to turn white. At fifty-six, his Liver Qi weakens, his sinews and vessels lose their flexibility, tiangui is exhausted, his essence diminishes, and his Kidneys decline; all the body’s functions are nearing their limits. At sixty-four, his teeth and hair fall out.

The Suwen also says that in ancient times, those who understood the way of nourishing life followed the changes of Yin-Yang and harmonized their methods of cultivation. They ate in moderation, kept regular hours, and did not overexert themselves. As a result, body and spirit remained in harmony, and they enjoyed the lifespan allotted by nature, passing away only after living beyond a hundred years. People today are different: they treat wine as water and take an unrestrained life for granted. They have sexual relations while drunk, indulging their desires until their essence is depleted and their original Qi damaged. They do not know how to preserve their essence, nor do they nourish their spirit at the proper times. They seek only immediate pleasure and become lost in indulgence; their routines have no regularity. So they grow old before reaching fifty.

I believe that in old age, people often become forgetful because their spirit is clouded, and they tire as soon as they move because their strength has weakened. The way of inner cultivation takes Shen and Qi as its foundation. If the spirit is clouded and strength has weakened, what foundation can there be?

The Yi Jing says, “Water comes one after another: this is the Repeated Kan hexagram.” Repeated Kan, with one Kan trigram placed above another, symbolizes dangers following in succession and reminds people to face them.

I also consulted the Ling Shu Jing: the movements of the sun and moon pass through the Twenty-Eight Lunar Mansions, and the circulation of the human meridians corresponds to them as well. … If the spirit is clouded and strength has weakened, what foundation can there be for the way of inner cultivation?

The Yi Jing says, “Water comes one after another: this is the Repeated Kan hexagram.”

I believe the Ling Shu Jing (Spiritual Pivot Scripture) says that the sun’s course passes through the Twenty-Eight Lunar Mansions, while the human body’s meridians comprise twenty-eight pathways running up and down, left and right, and front and back. They extend throughout the body and measure sixteen zhang and two chi in total, corresponding to the Twenty-Eight Lunar Mansions. The clepsydra, an instrument that measures time by dripping water, releases one hundred measures of water in a day and a night, marking the passage of time.

With each exhalation, the pulse beats twice and Qi moves three cun; with each inhalation, the pulse also beats twice and Qi moves another three cun. In one full breath, Qi moves six cun. In ten breaths, Qi moves six chi, while the sun advances two fen. In 270 breaths, Qi moves sixteen zhang and two chi, completing one circuit through the body; the clepsydra releases two measures of water, and the sun advances twenty-five fen. In 540 breaths, Qi completes two circuits through the body; the clepsydra releases four measures of water, and the sun advances forty fen. In 2,700 breaths, Qi completes ten circuits through the body; the clepsydra releases twenty measures of water, and the sun passes five lunar mansions and twenty fen. In 13,500 breaths, Qi completes fifty circuits through the body; the clepsydra releases one hundred measures of water, and the sun passes through the Twenty-Eight Lunar Mansions, bringing a day and night to an end. The movement of the pulse and Qi also completes one circuit. In all, Qi travels 810 zhang.

The Ling Shu Jing also says that Qi moves like flowing water and, like the sun and moon, never ceases. Thus the Yin meridians nourish the five organs, and the Yang meridians nourish the six viscera. Their circulation repeats without end, with no clear beginning or end: when one cycle finishes, another begins. I believe that when Qi and blood flow freely and continuously through the body, it remains at peace; when they become obstructed and stagnant, illness arises. The method of internal cultivation is to let each breath follow the next without interruption, like a continuous stream. In this way, true Qi can flow upward and downward, circulating freely like water.

The I Ching says that the Kan trigram symbolizes water and the moon, while the Li trigram symbolizes fire and the sun.

Xiang Ping’an says: The heart takes Kan as its substance and Li as its function, so it should be empty, still, and clear. The kidneys take Li as their substance and Kan as their function, so the Dantian—the place where essence and Qi are gathered and nurtured in internal cultivation—should be full and warm. The terms “Decrease” and “Increase” both involve the three Yang lines and the Li trigram: in the Decrease hexagram, Li fire rises upward; in the Increase hexagram, Li fire settles below. He also says that in the Decrease hexagram, the fire that is the substance of Li rises upward, while in the Increase hexagram, the fire that is the substance of Li settles below.

I believe the method of internal refinement is extremely simple: one need only let the fire in the heart descend into the Dantian (energy center). The Dantian lies behind the navel and in front of the kidneys, right at the center of the abdomen.

Practitioners of alchemy sometimes avoid the words “heart and kidneys.” They say that the heart and kidneys are not Kan and Li—the trigrams in the Book of Changes that symbolize water and fire—and instead call the breath Kan and Li. But they have not considered that the breath is only the activity of Kan and Li, while the heart and kidneys are their source. The heart governs the human body, so it is at the center; the kidneys are its foundation, so they are in the lower part. Alchemical practitioners speak of “body and heart” rather than “heart and kidneys,” but here “body” means the abdomen, and the kidneys are in the abdomen too. How, then, can they be left out? The kidneys belong to water, and the heart belongs to fire. When fire enters water, water and fire mingle and unite, like the sun and moon joined together between the last and first days of the lunar month.

The Book of Changes says, “The energies of mountains and marshes communicate with one another.” It also says, “Yin and Yang energies respond to each other and join together.”

I have examined a passage in the Cantong qi: “This happens naturally; it is not contrived through delusion. The Dao is like the vapors rising between mountains and marshes, giving rise to clouds and transforming into rain.” This means that the Yin and Yang energies within the human body mingle and gather in the Dantian, then rise to the Niwan, the central region inside the head, surging like clouds and transforming into sweet dew.

A poem by Chen Xiyi, a Daoist of the Northern Song, says: “Suddenly the wheel of fire boils, stirring the earth’s veins; in awe, I see the divine spring surge up to the mountain peak.” This expresses the same idea. The Liezi mentions the “divine spring.” I once thought that the energies of mountains and marshes can communicate because there is emptiness within them. Only in emptiness can Yin and Yang energies respond to each other and unite. If they are blocked, they cannot communicate—so how could they join together? Internal refinement depends on making the heart empty and still. When the heart is empty and still, the spirit settles; when the spirit settles, Qi gathers; when Qi gathers, clouds arise and turn to rain. This resembles the way energies communicate between mountains and marshes.

The “Far Roaming” section of the Lisao says: “The Dao can be received, but it cannot be taught. It is so small it has no interior, and so vast it has no bounds. Do not disturb your spirit; it will follow its own course. Make the primordial Qi single and the spirit full, and nourish them at midnight. Wait for them in emptiness and stillness: this is the foundation of Wuwei (non-action).” Zhu Ziyang (Zhu Xi) comments that this is all Guangchengzi told the Yellow Emperor; indeed, these are essential instructions for cultivating immortality.

The Book of Changes says: “Opening and closing are called change; coming and going without cease are called free passage.”

Cheng Yichuan said, “The way to cultivate and preserve oneself lies in the outgoing and incoming of the breath. Breathing is the pivot of Yin-Yang opening and closing.” He also said, “The opening and closing, coming and going of Yin-Yang can be seen in the breath through the nose.”

Zhang Hengqu said, “Human breathing is much like the interplay of firmness and yielding; it is a sign of Heaven and Earth opening and closing.” Zhu Ziyang wrote in his “Admonition on Regulating the Breath,” “Qi drifts and flows, opening and closing, its transformations endlessly subtle. Who governs it all? In truth, it is the workings of Wuwei (non-action) and nature.”

I believe the Cantong qi (Token for Joining the Three) says, “The two functions of Yin and Yang have no fixed positions among the lines; they circulate through the six empty places. Their comings and goings have no set location, nor do their movements up and down follow any constant pattern. They are hidden and concealed, and transformation takes place within them.” Here, “two functions” refers to the two kinds of Yin-Yang lines, nine and six, while the “six empty places” refers to the six line positions of a hexagram. They serve as metaphors for each inhalation and exhalation, for coming and going, rising and descending. When the breath continues to flow for a long time, the spirit becomes settled and the breath grows calm; transformation then arises. In exhalation, Qi moves outward: this is Yang opening. In inhalation, Qi moves inward: this is Yin closing. The Yin-Yang within the human body resembles the Yin-Yang of Heaven and Earth. If one can let the breath move between above and below, circulating without cease, then the subtle workings of Yin-Yang opening and closing, coming and going, are all present within oneself.

Some say that a broad realm has broad opening and closing, while a small realm has small opening and closing. The opening and closing within a single breath corresponds to that within a quarter of an hour; a quarter of an hour corresponds to an hour, an hour to a day, a day to a month, and a month to a year. Extend this through a lifetime, a great calendrical cycle, and even the ages of antiquity, and the principle of opening and closing remains the same.

The Book of Changes says, “When the sun sets, the moon rises; when the moon sets, the sun rises. The sun and moon alternate in their courses, and light comes into being. When cold passes, heat arrives; when heat passes, cold arrives. Cold and heat alternate in their courses, and the year takes shape.”

Cheng Yichuan said that what the Book of Changes describes is simply coming and going, back and forth, rising and descending. I believe that although the writings of the alchemists use many metaphors and indirect explanations, they too speak only of coming and going, back and forth, rising and descending. Any claims beyond this are misguided and reckless; they are not the foundation of the natural Way.

I believe the Wenzi says: “Running water does not go foul because it keeps flowing; a door hinge is not eaten by worms because it is often turned.” The Wenzi is Jiran, a man of the Zhou dynasty and a disciple of Laozi. A person’s Qi and blood should also circulate back and forth. When they become blocked, a small obstruction may form a boil, and a larger one may form a carbuncle. A boil is a localized lump; a carbuncle is congestion; and a deep abscess is stagnation.

I also believe the Zihuazi says: “In ancient times, those who understood the Dao built defensive ramparts to ward off pernicious influences and cleared the source to nourish true Qi. They dwelt in quiet seclusion, undisturbed by external things. Their inhalation and exhalation accorded with Shen and Qi; they guarded their souls, remained vigilant, and closed the sensory gates of ears and eyes, keeping their minds focused and undistracted. In this way, true Qi could be preserved.” The “deep abscess” mentioned here means stagnation.

I also consulted the book Zihuazi, which says: “In ancient times, those who understood the Dao built protective barriers to ward off harmful influences and cleared the source to nourish true Qi. They lived in quiet places, undisturbed by external things. As the breath flowed in and out, they brought spirit into harmony with the breath. They kept their hun and po souls within the bounds of discipline, carefully gathering the mind and not letting it become scattered. When the will was focused, true Qi could be retained. When the breath flowed freely up and down, the movement of Qi could proceed without obstruction, like flowing water and the ceaseless courses of the sun and moon. Yin Qi nourished the organs within, while Yang Qi strengthened the body’s inner chambers. The currents of Qi flowed continuously, abundant without spilling over, and moving freely without becoming congested. This is what is meant by nourishing life over the long term.”

Zihuazi was named Cheng Ben. Tradition says that he once spoke with Confucius; they met while riding in carriages, their carriage canopies touching as they talked.

Qi and blood move up and down through the human body in an unbroken cycle, day and night, like the waters of a great river. People see only the river flowing east into the sea and seem never to run dry, but do not realize that famous mountains, great rivers, and underground passages are connected to one another. Why does the Lushan Waterfall pour without ceasing, day and night? Because water flows underground and circulates back and forth. The sun and moon move in the same way: as the celestial bodies turn, they emerge and withdraw, passing back and forth without end. If people understand that their own bodies, too, have a mechanism of cyclical movement like that of the sun and moon, they will see that this boundless wonder lies within their own bodies; there is no need to seek it in some distant, lofty place.

Medical texts say that the human body has the Ren and Du meridians. The Ren meridian begins below the Zhongji acupoint, rises past the pubic hairline, runs upward along the inner abdomen to the Guanyuan acupoint, and then reaches the throat. It is where the Yin meridians converge. The Du meridian begins at the acupoint below the lower pole, runs up along the spine to the Fengfu acupoint, enters the brain, rises to the crown of the head, and then follows the forehead to the bridge of the nose. It is where the Yang meridians converge. The Ren meridian is so named because women rely on it to conceive and nurture a child; the Du meridian is so named because it governs the various meridians. Deer are said to turn the tailgate—the area near the tailbone—to open the Du meridian, while turtles are said to breathe in slowly through the nose to open the Ren meridian. If people can open the Ren and Du meridians, all the other meridians will open as well.

The Huangting Jing says: “All within the heart, circulate the celestial pathway; keep it in mind day and night, and you will naturally attain long life.” The “celestial pathway” here refers to the routes of circulation within the body—that is, the Ren and Du meridians. The breath moves back and forth along this pathway.

The work on the right, A Separate Transmission Beyond the Yi, consists of one volume, illustrated with diagrams and explanatory notes. It sets out to clarify the subtle principles contained in the Xiantian diagram. Drawing on such texts as the Cantong qi and the Yinfu jing, and also on the incisive discussions of Confucian scholars such as Yichuan and Hengqu, it aims to explain what Zhu Xi left unexpounded and to bring out the deeper meaning beyond Shao Yong’s words.

Although I have not had the time to devote myself fully to this Way, the wonders of the alchemical methods—the Daoist methods of Neidan cultivation—cannot be understood merely by hearsay. I have tried them myself. I therefore dare to state plainly what the alchemists keep secret, so as to dispel the doubts of those who seek to learn. I have often lamented that the alchemical books circulating in the world rely on obscure and difficult language, leaving readers with no way in. Their eyes and minds grow confused as they read, until they can only close the book and heave a long sigh.

Cai Jitong and Yuan Jizhong once worked with Zhu Xi to collate the Cantong qi. Though they could examine the meanings of its words and phrases, they had not received the authentic transmission and could hardly avoid relying on conjecture. Now that I have received the transmission, how could I bear to keep it hidden for myself? I have therefore written this book and appended it to the Collected Explanations of the Zhouyi, giving it the title A Separate Transmission Beyond the Yi.

The title means that although the alchemists’ teachings derive from the Yi, they merely use the Yi’s forms as a vehicle; they are not the original meaning of the Yi. The relevant details are discussed at length in the three sections of Elucidating the Cantong qi, so I will not repeat them here. Written by Yu Yan of Shijian.

The Yuan dynasty Confucian scholar Hu Shuanghu wrote three essays called Commentaries on the Wings of the Zhouyi. He also collected works such as the Taixuan, the Cantongqi, and the Dongji, compiling them as an “Outer Section.” Yu of Shijian likewise wrote Essentials of the Great Change and Collected Explanations of the Zhouyi. He included the theories of the Former Heaven Diagram, the Secret of the Central Ring, and Wei Boyang’s Cantongqi, bringing them together as Separate Teachings Beyond the Changes. The range of material he drew from the Changes was, one might say, exceptionally broad.

The Commentaries on the Wings of the Zhouyi was once printed and circulated. Essentials of the Great Change and Collected Explanations of the Zhouyi were also printed in Gusu in the past, but are now difficult to find. A friend, Xu Yiyuan Ao, gave me this copy of Separate Teachings Beyond the Changes; I believe it too was printed in Gusu. The book expounds Shao Yong’s theories at considerable length, which helps in understanding the Changes.

This accords with what Zhu Xi meant when he said that the principles of the Changes encompass everything. As long as an interpretation forms a coherent system and can be developed consistently, it does not undermine the principles of the Changes. People sometimes force explanations out of practices such as alchemical furnace work, however, and that is a misunderstanding.

Shijian also wrote Elucidating the Cantongqi. Since that work has no direct connection with the Changes, I will not discuss it further here. In the xinsi year of the Zhengde reign, Huang Gong of Puyang wrote this at the Thatched Hall on Meng Mountain.

Separate Teachings Beyond the Changes