Laozi is a representative figure of Taoism in the pre-Qin period. In his book Tao Te Ching, there is the theory of internal strength training of "returning to the roots", the breathing skills of "hissing or blowing" and "continuing if there is one", and the ideal of "long life and long sight". In Zhuangzi, there are also some internal exercises, such as "fasting in the heart" and "forgetting to sit".
Wei Boyang in the Eastern Han Dynasty wrote Zhouyi Shentongqi, which was the ancestor of Danfa. Ge Hong in the Eastern Jin Dynasty was a theorist and practitioner of Taoism at that time. He thinks that the way of elixir is the acme of the way of immortals. "Bao Puzi Jin Zidan" said: "I have studied the Book of Toning Heaven and collected many books for a long time. I have covered thousands of volumes, all of which are mainly Hui Dan and Jin Ye. However, these two things are excellent. Take this instead of becoming an immortal, and there are no immortals in ancient times. "
The word "Inner Dan" was first seen in Xu Xun's Ling Jian Zi in the Eastern Jin Dynasty: "Take medicine and adjust your throat with Inner Dan". Master Huisi, the third ancestor of Tiantai Sect of Nanyue Buddhism in the Liang Dynasty in the Southern and Northern Dynasties, said in "Police Wishes": "I went into the mountains for asceticism and repented of the crime of breaking the precepts and obstructing the Tao. I'm sorry for my sins. I want to live a long life for my enemies. I don't want to live in heaven for pleasure. I hope the sages and sages Zuo Zhu and I can get good Cao Zhi and Shen Dan, cure all diseases and get rid of hunger and thirst, and often practice meditation. I hope to get a quiet place in the mountains. If you are tied, you can untie him, and nothing will happen. " This is the first book that clearly distinguishes between external Dan and internal Dan.
In the Sui Dynasty, Taoist Su further put forward the theory of "double cultivation", emphasizing the comprehensive exercise of body and mind, which further promoted the development of Inner alchemy.
The Tang and Five Dynasties was a crucial period for the development of Neidan Taoism. Zhong Liquan wrote Lingbao Dafa and preached the Tao, Shi Jianwu wrote Biography of Zhong You, Cui Xifan wrote Medicine Mirror, Sima wrote Introduction to Heaven, and Chen Tuan wrote Zhixuan Pian, Taiji Tu and Wuji Tu, which further improved the theory and method of the Tao of Inner Dan.
When Neidan was sent out in the Song and Yuan Dynasties, the Five True Chapters emphasized that to refine Neidan, we must first accumulate virtue: "Virtue has been cultivated for more than 800 times, and Yin Gong has accumulated for 3,000. Everything blends with me and my loved ones, and it is only in line with the wishes of the gods. " The inheritance system of Zhang Boduan alchemy is Shitai-Xue Daoguang-Chen Nan-Bai Yuchan, and the school that formed alchemy is called Nanzong. In addition, Wang Zhongyang initiated Quanzhen religion, saying that the true biography of Lu, Neidan is also the first task. He advocates double cultivation of life, clear mind and clarity, and taking cultivation as the first priority. The school spread by Wang Zhongyang is called Beizong. Later, there was a middle school founded by Li Daochun in Yuan Dynasty. Eastern learning founded by Lu in Ming Dynasty: Western learning founded by Li in Qing Dynasty. In addition, it is said that there are many hidden sects in Neidan. In ancient times, the teaching of Inner alchemy was mostly passed down from master to apprentice, which was difficult for outsiders to understand.
There are differences in the order of inner alchemy, which can be generally divided into several stages: building foundation, refining qi, refining qi spirit and refining spirit into emptiness. In the Yuan Dynasty, Chen wrote in four volumes of "Essentials of Elixir": "Yes, it is nothing more than three things, and it is based on the feeling of three things. Shun is an adult, and reverse is an elixir. What is Shun? A person's life is two, two gives birth to three and three gives birth to everything, so it is illusory, deified, refined and in the shape of an adult. What is inverse? Everything contains three, three returns to two, and two returns to one. Those who know this way are happy to keep shape, cultivate shape and refine, accumulate essence, refine qi and meet the spirit, and refine the spirit is still empty, then the elixir will succeed. "