The chinese Yin Yang symbol aka Taiji Symbol is by now synomymous with Taijiquan. You would never believe it but the Taiji symbol was not an aribitrary symbol birthed out of someone’s imagination. It was actually plotted from the shadow of a pole stuck in the ground as the sun rotated. The contrasting light and dark portions actually denote seasonal changes on the earth.
In the diagram above, a curved line divides the circle into two halves, of white and black. The white half represents Yang and the black represents Yin. There is a black dot in the white half and a white dot in the black half. This symbolises that there is Yin in Yang and there is Yang in Yin. When you separate the two halves, they actually resemble two fishes; if you look carefully. This symbol is closely related to Zhou Dunyi’s Diagram of the Supreme Ultimate. The theory goes that everything in the universe forms a unified whole made up of the two opposite and complementary forces of Yin and Yang. The symbol has been drawn in such a way that if you were to cut this circle in half with a straight line through its centre, both halves will always contain both Yin and Yang elements, no matter how cut it. It is supposed to prove that none of its components can ever be independent and free of internal tension.
Now, that’s what we call Taiji!