Neidan
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 (Skar and Pregadio 2000, 464). 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 Daoist meditation, daoyin gymnastics, and sexual hygiene (Baldrian-Hussein 2008, 762). 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., becoming an Immortal. 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". Chinese 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. The date for the earliest use of the term "neidan" is uncertain. 內丹 or "neidan" had been mention in《灵剑子》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  till the coming of Maitreya (1930: 14). 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"]. (1983: 140) Others believed that "neidan" first occurred in the biographies of Deng Yuzhi (fl. 483–493) and Su Yuanming (fl. c. 600). However, the authenticity of the relevant passages mention above is doubtful (Baldrian-Hussein 1989: 164–171 "pseudo-historical sources"). 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 (Baldrian-Hussein 2008: 763). Tang texts described internal alchemical practices with the words "fúyào" "take drug/medicine" and "chángshēng" "long life, longevity; (Daoism) eternal life" (Baldrian-Hussein 1989: 170). Liu Xiyue's 988 "Taixuan langranzi jindao shi" (Master Taixuan Langran's Poems on Advancing in the Dao) has the earliest datable mention of the terms "neidan" and "waidan" (Baldrian -Hussein 1989: 174, 178, 180). The c. 1019 "Yunji Qiqian" Daoist anthology mentions the term "neidan" (Baldrian-Hussein 1989: 178). 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" ) (Baldrian-Hussein 1989: 179–186). 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 (1989: 187). It is sometimes transliterated using the older Wade-Giles system as "Neitan" in literature on western Alchemy. History and development. Neidan is part of the Chinese alchemical meditative tradition that is said to have been separated into internal and external ("Waidan") at some point during the Tang dynasty. The "Cantong qi" (The Kinship of the Three) is the earliest known book on theoretical alchemy in China; it was written by the alchemist Wei Boyang in 142  AD. This text influenced the formation of Neidan, whose earliest existing texts date from the first half of the 8th century. The authors of several Neidan articles refer to their teachings as the Way of the Golden Elixir ("jindan zhi dao"). The majority of Chinese alchemical sources is found in the "Daozang" (Taoist Canon), the largest collection of Taoist texts. Neidan shares a significant portion of its notions and methods with classical Chinese medicine, "fangshi" and with other bodies of practices, such as meditation and the methods for "nourishing life" ("yangsheng"). What distinguishes alchemy from these related traditions is its  unique view of the elixir as a material or immaterial entity that represents the original state of being and the attainment of that state. The Neidan tradition of internal alchemy is practiced by working with the energies that were already present in the human body as opposed to using natural substances, medicines or elixirs, from outside of the body. The Shangqing School of Daoism played an important role in the emergence of Neidan alchemy, after using Waidan mainly as a meditative practice, and therefore turning it from an external to an internal art. The Three Treasures. Internal alchemy focuses upon  transforming the bodily "sanbao" "three treasures", which are the essential energies sustaining human life: According to the 13th-century "Book of Balance and Harmony": When the "three treasures" are internally maintained, along with a balance of yin and yang, it is possible to achieve a healthy body and longevity, which are the main goals of internal alchemy (Ching 1996, 395). Jing. "Jing" "essence" referring to the energies of the physical body. Based upon the idea that death was caused by depleting one's "jing", Daoist internal alchemy claimed that preserving "jing" allowed one to achieve longevity, if not immortality. (Schipper  1993, 154). Qi. "Qi" or "ch'i" is defined as the "natural energy of the universe" and manifests in everyone and everything (Carroll 2008). By means of internal alchemy, Taoists strive to obtain a positive flow of "qi" through the body in paths moving to each individual organ (Smith 1986, 201). Healing practices such as acupuncture, massage, cupping and herbal medicines are believed to open up the "qi" meridians throughout the body so that the "qi" can flow freely. Keeping "qi" in balance and flowing throughout the body promotes health; imbalance can lead to sickness. Shen. "Shen" is the original spirit  of the body. Taoists try to become conscious of "shen" through meditation (Smith 1986, 202).