According to legend, during the period of the Yellow Emperor, China's theory of traditional Chinese medicine has made great achievements. The Yellow Emperor and his minister Qi Bo are both experts in treating diseases. They often get together to discuss the theory of traditional Chinese medicine and the way of keeping in good health. Later, their conversation was recorded in Huangdi Neijing. Because Huangdi Neijing adopted the form of a question and answer between Huangdi and Qi Bo, the ancients used Huang Qi to refer to Chinese medicine in order to show their respect for their ancestors. Huangdi Neijing, Yijing and Daodejing are collectively called "Three Books", which have immeasurable influence on the development of China traditional culture.