YA yin, A yang, this is Tao. Chapter 5, Hsi-tz'u from I Ching

Yin and Yang, the two opposing energy forces which symbolise the two fundamental principles of the universe. Discover Yin and Yang with Ching Oracle! We often hear people speaking of Yin and Yang but only a few people really know their meaning and implication in Eastern culture (particularly Chinese). The origins and symbolic meanings of Yin and Yang are contained in this section, ready to be read by people who are fascinated by Eastern culture, like you!

Yin and Yang - two ancient entities, opposing but complementary, which symbolise the duality present in every element of the cosmos. Yin and Yang cannot live without one another, otherwise they would both be incomplete and the equilibrium of the entire universe could be compromised. The union of Yin and Yang form the Tao, present in any element and graphically made up of one black part and one white part. The black part, Yin, is the negative and feminine principle and the white part, Yang, is the positive, masculine principle. Yin, originally, was the name of the cold side of the mountain, the part facing north; on the contrary, Yang was the warmer side, facing the south.