Chinese people attribute an origin to every movement of matter and power to the constant equilibrating force of the positive and negative aspects of energy, called Yin and Yang. Yin and Yang are represented in the Chinese symbol of T'ai Chi (see the illustration). This circle symbolizes the origin of life. Yang (the light side) symbolizes birth (or the day) and Yin (the dark side) death (or the night). Since the two sides are perfectly balanced, the symbol is also called "Supreme Principle of all matter".