The Taijitu, often simply called the Yin Yang symbol in western countries, represents perfect and complementing balance. The dark side of the symbol is Yin, meaning "shady", and the light side is Yang, meaning "sunny".
Yin Yang is one of the most well-known concepts of Taoism. Yin Yang is described in the Tao Te Ching by explaining that when beauty is seen, ugliness is created and when good is seen evil is created. Neither of the complementing forces is absolute, as each side of the Taijitu contains a small part of the other. The shape of the two sides represents the desire for each part to adjust to the other to achieve balance. It is the ever-changing balance that forms the whole of an individual, society or universe.