which is used to explain the two opposing and mutually destructive forces in nature. The interaction of yin and yang drives the creation and change of all things and phenomena in the universe [2]. For this reason, ancient Chinese physicians concluded that "Yin and Yang have their own name, but no form" [3].The Yin-Yang doctrine states that everything in the universe can be divided into two categories: Yin and yang. Yin or yang alone can be divided into yin (sub-1) and yang (sub-1). Any yin (sub-1) or yang (sub-1) can also be divided into yin (sub-2) and yang (sub-2), and the list is endless [4].The division of yin and yang is based on sunlight, and anything that corresponds to the sunward side is yang, and the backward side is yin. In general, anything that is active, external, ascending, warm, bright, functional, hyper-functional, etc. is yang. Conversely, that which is internal, falling, cold, obscure, material, declining in function, etc., belongs to yin. The relationship between yin and yang has the following characteristics: