Yin & Yang | 陰陽
The theory of Yin and Yang is that anything or events in nature containing two aspects: Yin and Yang. Humans are considered to be an integral part of nature, composed of the most basic matter (named "qi") and its movement. This movement consists of two basic movements with different trends.
The basic idea of this principle is that Yin and Yang are mutually opposed and yet mutually interdependent, and they are always in motion and change. Under normal physiological conditions, the two are in a dynamic balance.
When the balance in our bodies is disrupted, the body will become abnormal and a state of illness will occur.