The Origins, Development, and Main Schools of Taoist Inner Alchemy

Hu Fuchen

Inner alchemy (neidan) is the chief method of practice in Taoism: a theoretical system and pattern of conduct that integrates the cosmology, philosophy of life, view of the human body, and practical experience of Taoist culture.

Inner alchemy seeks the state of the immortal, in which a person accords with the natural original nature of the universe and becomes one with the Tao. The state of the immortal is life's highest artistic state—utmost truth, utmost goodness, utmost beauty, the fullest expression of the value of life—and inner alchemy is a tunnel leading to it.

Inner alchemy is a cultural system that embeds the Tao in technique. Generation after generation of ancient inner alchemists, one following another and undaunted by setbacks, practiced and left behind thousands of alchemical scriptures, which are the experimental records of their systems engineering of the human body. Most of these scriptures, however, were written in coded language and verse, and the formulas of inner-alchemical practice were passed on secretly by word of mouth between master and disciple, which in effect served to protect intellectual property.

The great Way of the Golden Elixir is a way of the unity of heaven and humanity that joins heaven and earth, matches the sun and moon, accords with creation, returns to naturalness, restores the original self, and cultivates nature and life. Yet academia today regards inner alchemy as a lost learning of the ages; the practices circulating in society and the interpretations of alchemical scriptures are riddled with contradictions, and scholars with true insight into the matter are as few as morning stars. We should now strive to lift the veil of mystery shrouding inner alchemy and organize and study its materials with the tools of modern science and philosophy.

Inner alchemy originated in the primitive clan religion and shamanic-scribal culture of the ancient peoples. It was formed by the immortality seekers, who fused and sublimated the qi-circulation arts of Wangzi Qiao and Chisongzi, the arts of the bedchamber of Pengzu, Rongcheng Gong, the Mysterious Maiden, and the Plain Maiden, and the ingestion arts of Xianmen Gao and Anqi Sheng, handed down from antiquity.

“Far Roaming” in the Songs of Chu can be seen as an early document of inner alchemy; it reveals that Wang Qiao's method could stimulate the body's prior-heaven true qi. In inner alchemy, the true unified qi of prior heaven is written with a different character for qi, to distinguish it from the breath-qi of later heaven. Whether one can stimulate prior-heaven essence, qi, and spirit is the dividing line between inner alchemy and ordinary qi-circulation arts (qigong).

The pre-Qin Laozi and Zhuangzi are the works that laid the foundations of the theory and practice of inner alchemy. The intellectual system of the school of Laozi and Zhuangzi, its categories such as “the Tao,” “emptiness,” “stillness,” and “nothingness,” and its concepts of essence, qi, and spirit were not only carried on by inner alchemy; its practices—“attain utmost emptiness, keep to profound stillness,” concentrating the spirit, guarding the One, sitting in forgetfulness, the fasting of the mind—were also absorbed as inner-alchemy formulas. The states of the sage, the Perfected, and the immortal advocated by Laozi and Zhuangzi became the model of conduct and the ideal goal that inner alchemists followed.

The Laozi and Zhuangzi contain not only the philosophical realm of rational thought but also the artistic realm of intuitive thought and return to nature, and the realm of practice of clarity and stillness, non-action (wuwei), and oneness with the Tao. The Laozi contains passages on “concentrating qi to attain softness,” “embracing the One,” “being sparing with essence,” “the gate of the mysterious female,” “the valley spirit never dies,” and “long life and lasting vision.” This agrees with the statement in the Biographies of Immortals (Liexian Zhuan) that “Laozi loved to nourish his essence and qi, valuing union without emission”; it is an inner-refinement practice combining qi circulation and the bedchamber arts. The Laozi says: “One who holds virtue in abundance is like a newborn infant. Poisonous insects do not sting it, fierce beasts do not seize it, birds of prey do not strike it. Its bones are weak and its sinews soft, yet its grip is firm; it does not yet know the union of female and male, yet its member stirs—this is the height of essence. It cries all day without growing hoarse—this is the height of harmony. To know harmony is called constancy; to know constancy is called illumination; to add to life is called ominous; for the mind to drive the qi is called forcing” (chapter 55). This shows that the cultivation practice of the Laozi already briefly reflects the state of the yin-yang alchemical method.

The inner-refinement practice of the Zhuangzi leans toward pure cultivation; its specific methods appear mostly in the chapters “Nourishing the Lord of Life,” “Constrained in Will,” “Letting Be,” and “Mastering Life.” The chapter “Letting Be” describes the art of guarding the One: “Do not look, do not listen; embrace the spirit in stillness, and the body will right itself. Be still, be clear; do not weary your body, do not agitate your essence, and you may live long.” The chapter “In the World of Men” describes the method of “the fasting of the mind”: “Unify your will. Do not listen with the ears but listen with the mind; do not listen with the mind but listen with the qi! The ears stop at hearing, the mind stops at tallying. Qi is empty and waits on things. The Tao gathers in emptiness alone. Emptiness is the fasting of the mind.” And: “Look at that empty space: the empty room gives birth to brightness; good fortune rests in stillness.” These words vividly reflect the state of practice of pure cultivation in inner alchemy. “The Great and Venerable Teacher” says: “I let go of my limbs and body, dismiss my perception and intellect, leave form behind and cast off knowledge, and become one with the Great Pervader—this is called sitting in forgetfulness.” It also describes the states of practice by which one attains the Tao: “putting the world outside,” “putting things outside,” “putting life outside,” “the brightness of dawn,” “seeing the singular,” “without past or present,” and “neither living nor dying.” It is no accident that later inner alchemists of both the pure-cultivation and yin-yang schools took Laozi and Zhuangzi as their ancestors; the famous lines on refinement and nourishment in their books have always been the core of inner-alchemy formulas.

Among pre-Qin relics of inner alchemy there is also an heirloom jade object in the Tianjin History Museum, whose inscription is understood differently by the yin-yang and pure alchemical schools. The Jade Inscription on Circulating Qi (Xingqi Yupei Ming) reads: “In circulating qi, swallow it and it accumulates; accumulated, it extends; extended, it descends; descended, it settles; settled, it becomes firm; firm, it sprouts; sprouting, it grows; grown, it recedes; receding, it becomes heaven. The pivot of heaven moves above; the pivot of earth moves below. Following it, one lives; going against it, one dies.” According to the pure alchemical method, this describes the method of circulating qi: one should concentrate the spirit and gather the qi, move it down to the dantian (elixir field), enter concentration so that it congeals, give rise to true qi, turn it back up the Governing Vessel, and raise it to Niwan (the Muddy Pellet, crown center). Heaven (the head) is taken as the cauldron and earth (the abdomen) as the furnace, and one cultivates according to the workings of yin and yang. Those who follow this way extend their years; those who go against it shorten their lives.

In addition, the famous Yellow Emperor's Inner Classic (Huangdi Neijing) and the Yellow Emperor's Classic of the Hidden Talisman (Yinfu Jing) also contain hidden inner-alchemy formulas, which few scholars today have yet identified. Historical sources show that the immortality cults of the Qin and Han already transmitted the arts of inner-alchemy cultivation in secret; traces of this can also be found in Taoist books such as the Scripture of Great Peace (Taiping Jing) and the Xiang'er Commentary on the Laozi.

The Zhouyi Cantong Qi by Wei Boyang of the Eastern Han is the first work of immortality studies devoted specifically to inner-alchemy formulas. Using the hexagrams and lines of the image-and-number study of the Zhouyi (I Ching) as symbols, the laws of the movement of the sun and moon as its theoretical framework, and the reaction of lead and mercury in the outer-alchemy furnace as its model, The Seal of the Unity of the Three (Cantong Qi) expounds the secret art of the mutual response of yin and yang and the union of the qi of man and woman. The learning of the Cantong Qi holds that the Earth Element method of furnace refining, the Human Element method of yin-yang grafting, and the Heaven Element method of pure solitary cultivation are interconnected and can be unified within the system of the Cantong Qi. The Cantong Qi recorded in coded language the secret formulas of the yin-yang school's method of dual cultivation of man and woman, linking pure cultivation with outer-alchemy furnace work, and was revered by later alchemists as “the king of alchemical scriptures for all ages.” Its transmission marks the formation of inner alchemy.

The Scripture of the Yellow Court (Huangting Jing), transmitted in the Wei-Jin period, and Ge Hong's Baopuzi (Inner Chapters) both conceal inner-alchemy formulas. The Scripture of the Yellow Court already began calling the inner elixir the “child elixir” and the “mysterious elixir,” focusing on a pure alchemical method centered on preserving the spirits, keeping the mind on the three dantian, inner vision, and regulating the breath. The Outer Radiance Scripture of the Yellow Court stresses the role of the Niwan Palace in the head in the work of refining the spirit. Its lines “Within is a Perfected wearing a golden turban, bearing armor and holding a talisman to open the seven gates; this is not branch and leaf but truly the root—think on it day and night and you may live forever” tacitly accord with the yogic practice of cultivating the seven chakras and represent the Central Yellow Direct Penetration method. The Baopuzi (Inner Chapters) also conceals two alchemical formulas: one is “the Perfected's art of guarding the body and refining the form” in the chapter “Subtle Import,” belonging to the pure method; the other is “the way of seeking life between the two mountains,” also in “Subtle Import,” belonging to the yin-yang method. The Inner Radiance Scripture of the Yellow Court already has the name “mysterious elixir” (“If you can preserve the mysterious elixir in the three palaces, the flowing pearl of Taiyi rests on Kunlun”), and the “Subtle Import” chapter of the Baopuzi speaks of the “middle elixir” (“The middle elixir shines brilliantly, alone without peer; establish it at Mingmen and the body will not perish”); in fact they already called the method of circulating true qi “refining the elixir.” In the Vow Text of the Great Chan Master Si of Nanyue, the monk Huisi, third patriarch of the Tiantai school, drew Taoism into Buddhism, “seeking long life for the sake of protecting the Dharma” and “borrowing the power of the outer elixir to cultivate the inner elixir, wishing to set sentient beings at peace by first setting oneself at peace,” so that the names outer elixir and inner elixir appear in the historical record.

In the Sui and Tang, the Zhouyi Cantong Qi circulated openly in society, promoting the development of inner alchemy. According to the Gazetteer of Mount Luofu, Su Yuanlang, called Qingxiazi, came to live on Mount Luofu in the Kaihuang era of the Sui and turned the divine elixir inward into refining the mind; “from then on Taoists first knew of the inner elixir.” Among Tang alchemists, Zhang Guo and Sima Chengzhen made the most notable contributions to the development of inner alchemy.

From the late Tang and Five Dynasties to the early Northern Song, inner alchemy suddenly flourished and came to dominate Taoist methods of cultivation. Famous inner alchemists and eminent Taoists such as Cui Xifan, Zhongli Quan, Lü Dongbin, Chen Tuan, Liu Cao, Shi Jianwu, Chen Pu, and Tan Qiao transmitted the practice and guided others through inner alchemy, bringing its methods to maturity and perfection.

Cui Xifan's verse formulas, Master Cui's Mirror for Compounding the Medicine (Cuigong Ruyao Jing), were esteemed by alchemists of every age; they are in fact secret formulas of yin-yang dual cultivation. The deeds of Zhongli Quan and Lü Dongbin were deified by later Taoist priests, and alchemists of all schools mostly acknowledge Zhong and Lü as their founding patriarchs; without Zhong and Lü, the history of inner alchemy could not be told. Shi Jianwu, a disciple of Lü Dongbin, wrote the Collected Transmission of the Tao from Zhongli to Lü (Zhong Lü Chuandao Ji) and the Record of the Assembled Immortals of the Western Hills (Xishan Qunxian Huizhen Ji), expounding the alchemical method of Zhong and Lü, which greatly influenced later generations.

There are also the Complete Methods of Numinous Treasure (Lingbao Bifa), the Song of Breaking Delusion and Rectifying the Way (Pomi Zhengdao Ge), and others, all bearing the names of Zhong and Lü as authors. Among them, the Song of Striking the Lines (Qiaoyao Ge), traditionally attributed to Lü Dongbin, contains the formulas of yin-yang dual cultivation. The Zhong-Lü alchemical method is a systems engineering of the human body based on dual cultivation of nature and life and the joint refining of body and spirit. It takes the congealing of essence, qi, and spirit as its basic skill and the capturing of the one qi of prior heaven as its key formula; its stages are clearly defined and each step has its signs of verification, drawing many seekers of the Tao to devote their lives to this experiment on the human body. It is said that Zhongli Quan obtained the alchemical formulas and transmitted them to Lü Dongbin, Chen Pu, and others, and that Lü Dongbin's disciples included Liu Cao (Perfected Liu Haichan), the Hemp-Robed Taoist, Shi Jianwu, He Changyi, and Zhang Zhongfu.

Chen Pu wrote Master Chen's Formulas of Inner Alchemy (Chen Xiansheng Neidan Jue), included in the Taoist Canon (Daozang); its formulas point directly to the Mysterious Pass and achieve success in nine turnings. Lü Dongbin's disciple Liu Haichan in turn transmitted the method to Zhang Boduan, Cao Jiong, Ma Ziran, Lan Yuandao, Wang Tingyang, Zhang Jixian, and others, who became great masters of inner alchemy. Another key figure in the history of inner alchemy is the famous Taoist scholar Chen Tuan. Chen Tuan, styled Tunan and self-styled Fuyaozi, was granted the title “Master Xiyi.” He received the Zhong-Lü alchemical method transmitted by the Hemp-Robed Taoist, learned the art of locking the nose from He Changyi, and lived in seclusion on Mount Hua. Chen Tuan's learning was passed on to Zhong Fang, Zhang Wumeng, Perfected Huolong, and others, and Tan Qiao was his teacher-friend. Chen Tuan wrote Pointing to the Mystery (Zhixuan Pian) and transmitted the Diagram of the Ultimate of Nothingness (Wuji Tu), establishing the principle of the returned elixir—“following the ordinary course produces human beings; reversing it forms the elixir”—and the basic steps of “refining essence into qi, refining qi into spirit, and refining spirit to return to emptiness.” Chen Tuan also transmitted the “Hibernating Dragon method,” and the alchemical methods of all later schools were influenced by him.

From the Song dynasty onward, inner alchemy gave rise to many schools as it developed, and its methods gradually reached a state of perfect mastery, becoming a mature inner alchemy. Spread by Lü Dongbin, Chen Tuan, and Liu Cao, it later came to be divided into the Heaven Element, Earth Element, and Human Element methods, and its schools were transmitted as the Southern, Northern, Central, Eastern, and Western.

The Heaven Element method later generally refers to the pure cultivation of the Longmen (Dragon Gate) lineage of the Northern School, though traditionally the outer elixir that allows one to ascend on the spot after ingesting it was called the Heaven Element divine elixir. The Human Element method later generally refers to the Southern School's yin-yang dual cultivation of grafting between man and woman, though some call the methods of dual cultivation of nature and life of both the Southern and Northern Schools collectively the great Human Element elixir. The Earth Element method generally refers to the outer alchemy arts of yellow and white (gold and silver), called the Earth Element numinous elixir. All the schools of inner alchemy trace their origins back to Fuxi, the Yellow Emperor, Wang Qiao, Chisong, and Laozi. One school claims transmission from Guanyinzi (Perfected Wenshi) and is called the Wenshi school; it was passed by Chen Tuan to Perfected Huolong. Another relies on Wang Xuanfu (a man of the Han), the Divine Lord Shaoyang of the Purple Mansion of Eastern Florescence, and is called the Shaoyang school; it claims that Wang Shaoyang transmitted to Zhongli Quan, and Zhongli Quan to Lü Dongbin, who then opened the various alchemical schools of the Southern and Northern lineages. The Wenshi school takes emptiness and nothingness as its principle and belongs to the supreme and most perfect wondrous Way; it transcends suddenly and enters directly, cultivating nature while also cultivating life, and is the Heaven Element method. The Shaoyang school advocates dual cultivation of nature and life and the refining and nourishing of yin and yang, proceeding from methods of action to the method of non-action; its stages are clear and easy to begin, and it spread very widely. Hence the alchemists' saying that the Wenshi school is the highest and the Shaoyang school the largest. In fact, in terms of alchemical method, these many schools fall roughly into two kinds: the grafting method of yin-yang dual cultivation, and the method of embryonic breathing of pure solitary cultivation; the others are merely combinations of the pure and yin-yang schools.

The Southern School of inner alchemy regards Zhang Boduan as its founding patriarch. Zhang Boduan (987–1082), also named Yongcheng, styled Pingshu, and called Perfected Ziyang, was a native of Tiantai who attained the Tao late in life and wrote Awakening to Perfection (Wuzhen Pian), making public the secret inner-alchemy formulas of the Zhouyi Cantong Qi. Zhang Boduan transmitted to Shi Tai (called Xinglin), Shi Tai to Xue Daoguang (Dharma name Zixian), Xue Daoguang to Chen Nan (called Cuixu and known as Chen Niwan), and Chen Nan to Bai Yuchan (called Haiqiongzi and enfeoffed as Perfected Ziqing); these are revered by later generations as the Five Patriarchs of the Southern School. Zhang Boduan also transmitted to Ma Ziran, Liu Fengzhen, and others. Liu Fengzhen, that is, Liu Yongnian, styled Guangyi and called Shunlizi, transmitted the alchemical method to Weng Baoguang, and Weng Baoguang in turn to Ruoyizi; this is the method of yin-yang dual cultivation. Xue Daoguang left the Buddhist monkhood and returned to lay life in order to cultivate the elixir, and what he practiced was also the yin-yang formula. Bai Yuchan's alchemical method, by contrast, belonged to the pure-cultivation school; he had many disciples and formed a religious community, the best known of whom were Xiao Tingzhi, Wang Jinchan, Peng Si, Liu Yuanchang, Hong Zhichang, Taoyuanzi, and Lin Ziran.

Compared with the Northern School, the Southern School's method, while premised on dual cultivation of nature and life, lays more weight on the cultivation of life. It cultivates life first and nature after, technique first and the Tao after, forming a systems engineering of the human body with clearly defined stages. In the yin-yang grafting practice transmitted by the Southern School, at the step of refining essence into qi, one takes from the other party's body the yang line within Kan, the one qi of prior heaven, and unites it with the true yin within one's own Li to form the elixir. Lu Yanfu, Dai Tongfu, Lu Ziye, Zhen Jiuying, Tao Suxiang, Li Wenzhu, Peng Haogu, Qiu Zhao'ao, Fu Jinquan, and others all advocated the yin-yang alchemical method and revered the Cantong Qi and Awakening to Perfection, so that the yin-yang method became a hallmark of the Southern School.

The Northern School was founded by Wang Chongyang, founder of the Quanzhen (Complete Perfection) school in the Jin dynasty. Wang Chongyang (1112–1170), named Zhe, styled Zhiming, and called Chongyangzi, was a native of Shaanxi. At Ganhe Town he met extraordinary beings who taught him the alchemical formulas, and after three years of refinement his elixir was complete. Later Wang Chongyang traveled east to the Shandong Peninsula to spread the Tao and took as disciples Ma Yu (called Danyangzi, founder of the Yuxian branch), Tan Chuduan (called Changzhenzi, founder of the Nanwu branch), Liu Chuxuan (called Perfected Changsheng, founder of the Suishan branch), Qiu Chuji (called Changchunzi, founder of the Longmen branch), Wang Chuyi (called Perfected Yuyang, founder of the Yushan branch), Hao Datong (called Perfected Guangning, founder of the Huashan branch), and Sun Bu'er (Ma Yu's wife, called Qingjing Sanren, founder of the Qingjing branch). The inner alchemy Wang Chongyang created was a pure-cultivation formula combining Chan and Taoism. The Northern School's method puts the cultivation of nature before that of life and emphasizes the cultivation of nature; its representative is Qiu Chuji's Longmen branch. Its formula lies in subduing the mind and refining nature, closing off the four gates of eyes, ears, mouth, and nose so that no outer scene enters, making the mind like still water and nature like a bright mirror, uniting spirit and qi, and turning the light back in silent illumination, so as to transform the body's constitution. Wang Chongyang and the Seven Masters of Quanzhen all spent years cultivating the Tao in seated meditation, and after attaining the Tao all developed the latent powers of the body; the secret probably lies in the three words “the living dead.” The Quanzhen school merged the ways of Confucianism, Buddhism, and Taoism, and the Northern School of inner alchemy also absorbed the strengths of Chan, tantric Buddhism, and yoga, reforming and developing the inner-alchemy practice of the Southern School. Yet since the Southern and Northern methods both derive from the Zhong-Lü system of inner alchemy, they are essentially one: both are works of congealing and refining the body's essence, qi, and spirit. In fact, Ma Yu and Liu Chuxuan of the Northern School both practiced the dual cultivation method of man and woman. The line passed from Ma Yu, Song Defang, Li Shuangyu, and Zhang Ziyang to Zhao Youqin (Yuanduzi) and Chen Zhixu is a branch of the Northern School that advocates yin-yang dual cultivation.

In the early Yuan, the Quanzhen Taoist Li Daochun, styled Yuansu, called Qing'an, and also known as Yingchanzi, lived at Changsheng Temple in Yizhen, Yangzhou. He wrote the Collection of Centrality and Harmony (Zhonghe Ji), the Marrow of the Changes of the Three Heavens (Santian Yisui), and other books, and founded the Central Branch of inner alchemy. The Central Branch interpreted Confucian and Buddhist books such as the Doctrine of the Mean and the Heart Sutra through inner alchemy and used Chan methods of sitting meditation and investigation, pursuing illumination of the mind and seeing one's nature. Li Daochun took the single move of “guarding the center” as the key formula of his alchemical method, holding that this word “center” is the Mysterious Pass: recognize the center, guard it and bring about harmony, and one naturally reaches utmost emptiness and profound stillness, illuminates the mind and sees one's nature, and transcends directly to perfect and sudden awakening. The Central Branch's alchemical method is a pure-cultivation practice of illuminating the mind and seeing one's nature. The late-Qing Taoist Huang Yuanji, who wrote the Recorded Sayings from the Hall of Joyful Nurture (Leyutang Yulu), the Annotated Tao Te Ching, and the Essential Sayings of the Taoist School, took guarding the center as his consistent practice. Huang Yuanji held that gradual cultivation begins with refining essence into qi, and that apart from the single practice of guarding the center there is no other path to follow. The alchemical scripture Pointers on Nature and Life (Xingming Guizhi), transmitted in the Ming, also contains the key formula of guarding the center.

In the Wanli era of the Ming dynasty, Lu Xixing of Xinghua County, Yangzhou, founded the Eastern Branch of inner alchemy. Lu Xixing (1520–1606), styled Changgeng and called Qianxu, claimed through spirit writing that Lü Dongbin had descended to his thatched hall and personally taught him the alchemical formulas. Lu Xixing wrote the Commentary on the Zhouyi Cantong Qi (Zhouyi Cantong Qi Ceshu), the Discourse on the Mysterious Skin (Xuanfu Lun), Chapters on Correcting the Golden Elixir (Jindan Jiuzheng Pian), and other books, collected in the Collected Works of Fanghu Waishi (Fanghu Waishi Congbian), unlocking the secrets of the alchemical methods of the Cantong Qi and Awakening to Perfection. The Eastern Branch's method firmly advocates forming the elixir through grafting between man and woman; it is a superior practice for the middle-aged and elderly, suited to husband and wife cultivating together and succeeding together.

In the Daoguang era of the Qing dynasty, Li Xiyue of Leshan County, Sichuan, styled Hanxu and called Changyi Shanren, claimed to have obtained the inner-alchemy methods of Lü Dongbin and Zhang Sanfeng and founded the Western Branch. Li Xiyue regarded himself as the reincarnation of Lu Xixing and wrote the Secret Principles of the Three Carts (Sanche Mizhi), Talks on the Apertures of the Tao (Daoqiao Tan), Linked Discourses on Later Heaven (Houtian Chuanshu), and other books; he too transmitted the yin-yang method of dual cultivation of man and woman. The Western Branch's method lays its foundation in clarity, stillness, and naturalness and forms the elixir through the wondrous use of yin and yang: using the other's lead to refine and nourish one's own mercury, so that the other and oneself aid each other and those of the same kind replenish each other, attaining the goal of returning to the root and the origin.

At the end of the Ming, Wu Shouyang, an eighth-generation disciple of the Longmen lineage, called Chongxuzi, from Bixie Village in Nanchang, Jiangxi, obtained the alchemical formulas transmitted from the “Tiger-Skin” Perfected Zhang Jingxu through Li Xu'an to Cao Huanyang. He wrote the Direct Discourse on the Correct Principles of Celestial Immortality (Tianxian Zhengli Zhilun) and The Common Source of Immortals and Buddhas (Xianfo Hezong), advocating a pure alchemical method harmonizing the three teachings of Confucianism, Buddhism, and Taoism. In the Qing, Liu Huayang left Buddhism for Taoism and wrote the Treatise on Realizing Golden Immortality (Jinxian Zhenglun) and the Wisdom-Life Scripture (Huiming Jing), systematically organizing and developing Wu Shouyang's method; this became known as the Wu-Liu school. In recent times, Zhao Bichen wrote Clear Pointers to the Methods of Nature and Life (Xingming Fajue Mingzhi); having received the transmission of Chan Master Liaokong, a disciple of Liu Huayang, and of Liu Mingrui, he founded the Qianfeng school.

The Yuan-Ming Taoist Zhang Sanfeng is a famous inner alchemist who can stand alongside Lü Dongbin and Zhang Boduan. His alchemical method is said to have been transmitted from Perfected Huolong and is called the Hidden Immortals school (Yinxian Pai); its formulas take the strengths of both the pure and yin-yang schools. He wrote the Lyrics of the Rootless Tree (Wugenshu Ci), the Treatise on the Great Tao (Dadao Lun), the Plain Talks on the Mysterious Mechanism (Xuanji Zhijiang), and more. In the Qing there were more than ten alchemical schools tracing themselves to Zhang Sanfeng, such as the Ziran school and the Rixin school. The late-Yuan Taoist Wang Daoyuan, author of the Collection on Returning to Perfection (Huanzhen Ji), the Collection on the Mystery of the Tao (Daoxuan Ji), and other works, was also a great inner-alchemy master of his age.

In addition, the eminent Qing Taoist Liu Yiming, called Wuyuanzi, wrote the Twelve Taoist Books (Daoshu Shi'er Zhong), interpreting inner alchemy through Confucian Neo-Confucian learning. The Longmen Taoist Min Xiaogen, whose Taoist name was Yide, lived in seclusion on Mount Jingai and wrote the Heart Lamps of Mount Jingai (Jingai Xindeng) and the Collected Works of the Hidden Tower of Ancient Books (Gushu Yinlou Cangshu), expounding the Central Yellow Direct Penetration method, in which prior-heaven qi rises and falls straight along the seam of the spine. The Nanwu alchemical master Liu Mingrui, called Panchanzi, left the Three Taoist Books of Panchanzi (Panchanzi Daoshu San Zhong) and was also a great inner alchemist of recent times.

Since the Han and Tang there have been many more inner-alchemy masters who succeeded in cultivation, and works on inner alchemy number no fewer than a thousand. Among the schools of inner alchemy there are also the Qingcheng school, the Kongtong school, the Nangong Sword Immortals school, and, among the thunder-rite traditions, the Shenxiao (Divine Empyrean) school, the Qingwei (Pure Subtlety) school, the Tianxin (Heart of Heaven) school, and others, each with its own distinctive features.

(Hu Fuchen, born in 1945, holds a doctorate in philosophy and is a research fellow at the Institute of Philosophy of the Chinese Academy of Social Sciences.)