Neidan, or internal alchemy (), is an array of esoteric doctrines and physical, mental, and spiritual practices that Taoist initiates use to prolong life and create an immortal spiritual body that would survive after death. Also known as Jindan ( "golden elixir"), inner alchemy combines theories derived from external alchemy (waidan ), correlative cosmology (including the Five Phases), the emblems of the Yijing, and medical theory, with techniques of Taoist meditation, daoyin gymnastics, and sexual hygiene.
In neidan, the human body becomes a cauldron (or "ding") in which the Three Treasures of Jing ("Essence"), Qi ("Breath") and Shen ("Spirit") are cultivated for the purpose of improving physical, emotional and mental health, and ultimately returning to the primordial unity of the Tao, i.e., attaining Taoist Immortality. It is believed the Xiuzhen Tu is such a cultivation map. In China, it is an important form of practice for most schools of Taoism.
Terminology
The Chinese compound nèidān combines the common word nèi meaning "inside; inner; internal" with dān "cinnabar; vermillion; elixir; alchemy". The antonym of nèi is wài "outside; exterior; external", and nèidān "internal elixir / alchemy" was coined from the earlier complementary term wàidān "external elixir / alchemy".
Traditional Chinese medical alchemical texts and sources ordinarily call neidan the jīndān dào or Way of the Golden Elixir. In Modern Standard Chinese usage, the term nèidān shù (with "art; skill; technique; method") refers generally to internal alchemical practices for longevity by maintaining good health, and the prevention of pain and suffering.
The date for the earliest use of the term neidan is uncertain. or neidan had been mentioned in by Xu Xun 许逊 in Jin dynasty (266–420) , but in the other hand Arthur Waley proposed that it was first recorded in the 559 vow taken by Tiantai Buddhist patriarch Nanyue Huisi praying to successfully make an elixir that would keep him alive until the coming of Maitreya. Many scholars agreed, including Joseph Needham and Lu Gwei-djen who translated Huisi's vow to live as an ascetic in the mountains: I am seeking for the longevity in order to defend the Faith, not in order to enjoy worldly happiness. I pray that all the saints and sages will come to my help, so that I may get some good magic mushrooms [zhi ], and numinous elixirs [shendan ], enabling me to cure all illnesses and to stop both hunger and thirst. In this way I shall be able to practice continually the way of the Sutras and to engage in the several forms of meditations. I shall hope to find a peaceful dwelling in the depths of the mountains, with enough numinous elixirs and medicine to carry out my plans. Thus, by the aids of external elixirs [waidan] I shall be able to cultivate the elixir within [neidan].Others believed that neidan first occurred in the biographies of Deng Yuzhi (fl. 483–493) and Su Yuanming (fl. ). However, the authenticity of the relevant passages mention above is doubtful.
The term neidan was seldom used throughout the late Tang dynasty (618–907) and Five dynasties (907–960) period, and only became widespread around the beginning of the Song dynasty (960–1279) period, when neidan evolved into a highly complex system in both its theoretical and practical aspects. Tang texts described internal alchemical practices with the words fúyào "take drug/medicine" and chángshēng "long life, longevity; (Taoism) eternal life". Liu Xiyue's 988 Taixuan langranzi jindao shi (Master Taixuan Langran's Poems on Advancing in the Tao) has the earliest datable mention of the terms neidan and waidan. The Yunji Qiqian Taoist anthology mentions the term neidan.
Early texts that mention neidan define it as synonymous or similar with some qi circulation techniques: Cultivation and Transmutation (xiulian ), Embryonic Breathing (taixi ), the Cyclical Elixir (huandan ), the Golden Elixir (jindan ), the Great Elixir (dadan ), the Interior and Exterior Medicines (nei/waiyao ), the Inner and Outer Counterparts (nei/waixiang ), and the Yin Elixir and Yang Elixir (yindan and yangdan ).
Based upon the textual evidence, Farzeen Baldrian-Hussein concludes that in early texts, neidan refers to a specific technique, and by Song Emperor Zhenzong's reign (997–1022), the term designates a group of techniques, expressed in specific alchemical language.
It is sometimes transliterated using the older Wade–Giles system as Neitan in literature on western Alchemy.