____________________
Yin and Yang, opposite and complementary forces in Chinese thought, from Chinese words meaning “shaded” and “sunny.” Beginning in the early 4th century bc Chinese philosophers wrote about yin and yang in terms of the environment, especially the shaded and sunny sides of a hill. By the end of that century yin became associated with everything dark, moist, receptive, earthy, and female, whereas yang was bright, dry, active, heavenly, and male. Yin and yang were believed to combine in various proportions to produce all the different objects in the universe.
There is always an element of yang within yin and an element of yin within yang. Together they are symbolized by a circle divided into black and white sections, with a dot of white in the black portion and a dot of black in the white portion. This interaction indicates that the characteristics of yin cannot exist without those of yang, nor the characteristics of yang without yin. Chinese philosophers stressed the importance of balance between the two to ensure social and political harmony. Rebellion, floods, and disease were said to be caused by an imbalance of yin and yang. Fortune-tellers and doctors in China and later in Japan advised governments and individuals on ways to restore harmony in relationship to yin and yang.