Movements require 2 complementary parts of the body

When an infant simply moves an arm the whole body reacts and starts to move...this kind of uninhibited movement is of no help in Tai Chi, yet millions of students do it. Master Wu Chien Chuan's words are simple, unremarkable and yet fall prey time and again to "run of the mill" reasoning found in much modern Tai Chi. This is called "if one part moves, everything moves" ..."everything goes" faulty logic. In fact, without logical reasoning, it never occurs to students that holding "one part still" (inhibiting neural activity)is actually more of a skill than simply moving the other part which even an infant does constantly without inhibition. "As discussed before in "Uncovering the Treasure", Stephen Hwa, Ph.D., to achieve internal movements, the yin and yang must be paired to form a junction at the right place in the torso. If there is any movement in the yin, the junction will be altered and result in an entirely different kind of move. The Classical Tai Chi Square form provides a drill to tune the neuromuscular control of the student. Most beginners cannot keep their neural signals focused on a narrow segment of their body. The diffusion of the signal creates unintended movements. This is called sloppy movements. The correct Square Form movement should look crisp and robotic. To be able to keep part of the body still, by itself, is also important training to eliminate unwanted habitual movement. A good example on the importance of stillness (yin) is the sweeping leg move in which one stands on one leg and sweeps the other leg outward to kick the opponent's feet out from under him. During this move, if the body moves slightly with the sweeping foot, the power of the sweep will diminish. In addition, the knee of the standing foot will feel pain. Since that foot is firmly planted on the ground with the entire body weight on it, so any turn of the body above will result in torque in that knee joint causing pain or injuries (see Picture). In other words, the yin part of the body's alignment has to be instinctively maintained.