The studies of the Book of Changes and the ideas of yin - yang and the five elements have had a profound impact on Taoism.

The studies of the Book of Changes and the ideas of yin - yang and the five elements have had a profound impact on Taoism.

I. The Theory of Yin - Yang and the Five Elements and Taoist Doctrines

Zou Yan, a fangshi (a master of esoteric arts) in the late Warring States period, combined the theory of yin - yang with the theory of the five elements, forming the "theory of the cycle of the five virtues." He used this theory to construct the cosmogony, historical view, the technique of physical dissolution, and the theory attached to ghosts and gods in the Fangxian Dao. The Fangxian Dao in the pre - Qin period was the predecessor of Taoism. Therefore, from the perspective of its ideological origin, Taoism has long been closely related to the theory of yin - yang and the five elements. The fangxian Taoists in the Han Dynasty continuously applied the theory of yin - yang and the five elements to Taoist doctrines. The most obvious manifestation was the emergence of the Taiping Jing. The Taiping Jing is a Taoist classic that "takes yin - yang and the five elements as its foundation." The theory of yin - yang and the five elements is the main theoretical basis of the Taiping Jing. It holds that yin - yang and the five elements embody the principles of the way of heaven, which are constant and unchanging. People must absolutely comply with them and not deviate from this way. "The way has no strange words. Yin and yang are its application. Those who follow its governance will prosper, while those who lose it will be in chaos; those who follow its governance will be spiritual and wise, while those who lose it will find the way unfeasible." The principle of yin and yang pervades heaven and earth and is the application of the way. Whether things are big or small, as long as they follow the way, there will be no misfortune. If the way is lost today, great chaos will ensue. Thus, when yang is stable, all things will grow spontaneously; when yin is stable, all things will form on their own. The relationship between yin and yang can be mutually generated and transformed. When yin reaches its extreme, yang is born; when yang reaches its extreme, yin is born. Only when yin and yang are in harmony can the way be practiced. Other works such as Xiang'er's Annotations on Laozi and Zhouyi Cantongqi are also closely related to the theory of yin - yang and the five elements.

II. The Theory of Yin - Yang and the Five Elements and the Taoist Pantheon

The ideas of yin - yang and the five elements influenced the ancient religion, one of the predecessors of Taoism. The ancients endowed the worshiped gods with the attributes of "yin - yang" and "the five elements," thus organizing the spiritual world. This idea was completely retained by Taoism. For example, the Donghua Emperor and the Queen Mother of the West, whom Taoism worships, are also called the Wood Duke and the Metal Mother. Volume 668 of Taiping Yulan, citing Jixianlu, states: "The Wood Duke and the Metal Mother are the ancestors of the two qi, the origin of yin and yang, the masters of the immortals, and the predecessors of creation. They condense qi to become real and integrate with the way." Another example is the Zhenwu Emperor (or the Xuanwu Emperor), who is the god in charge of the north in the Taoist pantheon (the north belongs to water in the five - element system). The Taoist gods with the attributes of yin - yang and the five elements are also reflected in the inner - body gods. Based on the theological ideas of "harmony between man and nature" and "interaction between man and nature," Taoism believes that the human body is also a small universe. The gods in the universe have corresponding existences in the human body. There are the Lord of Heaven and the gods of yin - yang and the five elements in the sky, and in the human body, there is the "heart - sovereign" and the gods of left - yin, right - yang, and the five - element internal organs. The yin - yang attributes of the celestial gods and the internal - body gods are similar and interconnected.

III. The Relationship between the Ideas of the Book of Changes and Taoism

Taoism uses the ideas and symbol systems of the Book of Changes to explain the movement and changes of all things in the universe, and through these changes, it guides the cultivation of the human body to achieve harmony with nature. At the same time, it proposes corresponding ways of adaptation in response to social order and chaos. The cultivation of the human body is most closely combined with the ideas of the Book of Changes (mainly the Han - Dynasty studies of the Book of Changes), and the most prominent manifestation is in Zhouyi Cantongqi. Zhouyi Cantongqi is the earliest work that combines the theory and practice of Taoist alchemical tripod cultivation handed down to this day. Its central idea is to apply the way of yin - yang revealed in the Book of Changes, combined with the principles of Huang - Lao's naturalism, to expound on the matter of alchemical refining. Later works on internal and external alchemy all take this book as the fundamental basis for verification.

From the perspective of magical arts and rituals, Taoist talismans and both internal and external alchemy are closely related to the studies of the Book of Changes. Talismans are non - character - like patterns. Taoism believes that they can "dispatch ghosts and command gods" and "suppress demons and evil spirits." Taoism creates talismans based on the Book of Changes. There are many talismans named after hexagrams preserved in the Daozang.