I thought I’d share my translation of some analytical points from Yang Zhenji’s book regarding the kicks in taijiquan. I hope this adds some perspective on the issue raised in the Shiyongfa book: “When you do a pressing kick to someone, you must not use force.”
• The attacking movements of the Fen Jiao and Deng Jiao kicks in Yang Style Taijiquan without exception require standing straight on one leg, with a stable lower frame. To achieve a stable lower frame you must pay attention to the following: the straight standing leg must not be stiff, the torso must not draw up, and the qi should not float up; the lower form should possess a downward-sinking strength (下沉的力量). The classical taijiquan requirements, “an intangible and lively energy lifts the crown of the head,” “loosen the waist and qua,” “contain the chest and pull up the back,” “sink the qi to the dantian,” and “sink the shoulders and drop the elbows,” should all be implemented in these movements.
• The movement of the foot in both Fen Jiao and Deng Jiao is to lift the knee and employ the springy jin (彈勁) to kick out in an instant. It is not a use of the waist/kua jin (腰跨的勁), nor a use of strength from the thigh (大腿根也不用力). If you were to employ strength (用力) from the waist/kua, then it would change into a thrusting kick (chuai 踹 ), which is the foot method of other boxing styles. In contrast, according to the kicking method of Yang Style taijiquan, the use of strength from the waist/kua will cause your body to be uncentered, and the strength to dissipate and disintegrate. The characteristics of Yang Style taijiquan’s kicking method is completely in harmony with the idea expressed in the classics: “it is rooted in the feet, issued by the legs, governed by the waist, and expressed in the fingers. From the feet, to the legs, then to the waist, always there must be complete integration into one qi.” The foot that is kicking out is rooted in the other [standing] foot. The foot, waist, and kua link together to create a stable base. This is foundation for the other, kicking foot. Carefully ponder this method of using jin, and you will come to intuitively understand it in your mind.
—Yang Zhenji, 杨澄甫式太极拳 Yang Chengfu Shi Taijiquan, page 88. I’ve pasted in Yang Zhenji’s comments below.
Let me know what you think.