“Xin 心 (Mind)” is one of the key concepts in the four chapters of Guanzi. Together with Dao, qi 气 (air, or gas) and de 德 (virtue), the four concepts constitute a complete system of the learning of mind which is composed of the theory of benti 本体 (root and body), the theory of practice and the theory of spiritual state. Guanzi differentiates the two basic layers of mind—the essence and the function. It tries to attain a state of accumulated jing 精 (essence, anima) and nourished qi, in which qi is concentrated in a miraculous way, through a series of methods of mind cultivation and nurturing, including being upright, calm, tranquil and moderate, and to concentrate the mind and intention. The doctrine of mind of the four chapters of Guanzi influenced Daoism and Confucianism and is a key link in the history of Chinese thought. It is a prelude to the merger of Confucianism, Daoism and Buddhism.