yin-yang theory

Yin-yang theory is the Chinese philosophical concept that opposing forces are interconnected and interdependent in the natural world.

Yin represents darkness, passivity, and the feminine; yang represents light, activity, and the masculine.

Neither exists without the other, and each contains the seed of its opposite—visualized in the familiar black-and-white circular symbol.

The theory underlies traditional Chinese medicine, martial arts, and feng shui: Acupuncture aims to balance yin and yang in the body.