The Yin and Yang of the Tai Chi symbol represents two extreme forces united in one. By observing the movement of the form, you realize the coordination is powered by the internal energy directed by the practitioner’s mind. Energy flow not only gives the power to the movement, but also strengthens the practitioner’s mind and body. In my class, I use Yang style to illustrate the principle of Tai Chi. But any school of Tai Chi may be analyzed by the same principle.