Tai Chi, the Great Ultimate, that comes out of Wu Chi, the Non-Ultimate, is the Initiator of stillness and movement, and is the Master of Yin and Yang. The Great Ultimate divides in movement; in tranquility it returns to the Non-Ultimate.
Never too much; never too little; bend is aways followed by stretch. When my opponent is hard, I am soft, that means I evade; when I follow my opponent closely, that means to adhere. To fast movement I respond with fast movement; to slow movement, I respond with slow movement. Although there are innumerable variations, there is but one principle. Through familiarity (with the practice of Tai Chi) one will gradually learn to understand (feel) strength; then progress continues and one is becoming spiritual. However, no one can really understand Tai Chi without practicing for a long time.
The spine and head are held straight by strength, which is guided by the mind. Breathing sinks to the lower belly (dantian); and complete attention is both there and elsewhere. No sloping, no leaning, visible or invisible. Always maintain the center of gravity in good balance. While weight is on the left side be able to shift away completely. While weight is on the right side, also be able to empty it. Going up, be able to go higher and higher; going down, be able to go deeper and deeper; marching become longer and longer; retreating, become shorter and shorter. The balance is so perfect (and the sensitivity so keen) that a feather cannot be added, neither can a fly find rest. People do not know me (my strength), yet I know them (their strength). This is the reason a hero is always matchless.
There are many different schools of combat, but their techniques always rely on strength (of the powerful) in overcoming the weak, the fast overcoming the slow. This is a matter of natural ability and has very little to do with learning. Consider the saying, “[A stretch of] four ounces can move a thousand pounds.” An old man can defend himself against many people. Obviously it is not a matter of mere strength and speed.
Stand like a perfectly-balanced scale, move (energy) as lively as a turning wheel. Be in good balance, yet emphasize on one side so movement can flow. Double-weightedness (weight equally distributed while moving) causes clumsiness. Often one sees people with quite a few years of practice who cannot use Tai Chi Chuan properly and are defeated because they do not understand the faults of Double-weightedness. To avoid this fault, one must know Yin and Yang. To adhere is to evade; to evade is to adhere. Yang is never without Yin, Yin is never without Yang. Yin and Yang help each other. You will understand strength once you achieve the ability to put this into practice.
When you have understood strength, the more you practice the better you will be. With sincerity through practice you will gradually be able to follow the wishes of the mind. While this means to give up yourself to follow the other, often it has been misunderstood as to give up the near for the far. This mistake of inches but an error of a thousand miles. Students of Tai Chi Chuan therefore must give it careful consideration. This completes the treatise.