In researching classic texts and books by past masters for the previous page the question came up, where does tucking the tailbone come from? From personal experience the two names that are most often associated with this practice are Cheng Man-ch’ing and Wang Xiang-zhai. Many of the instructors who are or claim to be in the Cheng Man-ch’ing line of Tai Chi actively practice and encourage tucking the tailbone. Where they got this idea is unknown but they assuredly did not get it from Cheng himself. Cheng Man-ch’ing did not practice tucking the tailbone as evidenced by his high level of skill. Additionally in his book Cheng Tzu’s Thirteen Treatises on T’ai Chi Ch’uan, he states the importance of the relationship between the position of the tailbone and the function of the autonomic nervous system.

“The sympathetic nervous system is the spine, and its function is dissipation. The function of the para-sympathetic is recovery. How can you recover through the para-sympathetic nerves? You accomplish this through the diaphragm which naturally contracts, expanding the chest, and pressing down on the internal organs of the abdomen, which in turn stimulate the para-sympathetic nerves. This causes the breath and pulse to slow down and increase the flow of saliva. It decreases the blood sugar and lowers the blood pressure. It also facilitates the flow of urine and reduces fever. This is all a result of the ch’i sinking to the tan t’ien and the coccyx standing straight so that the shen goes through to the headtop.”[1]

If asked about tucking the tailbone to eliminate the lumbar curve of the spine, Cheng would have undoubtedly been critical of the practice because it violates the relationship between the tan tien, coccyx, and head.

    If Cheng did not encourage this practice, this leaves Wang Xiang-zhai as a possible source. Wang also did not practice tucking the tailbone to eliminate the lumbar curve as again evidenced by his high level of skill. According to the articles and texts by and about Wang, he never mentions tucking the hips upward to eliminate the lumbar curve of the spine. But in his writings he does mention having the “pelvis tucked under.” Cheng Man-ch’ing was a very educated man and obviously had some knowledge of anatomy. However Wang Xiang-zhai was uneducated, but that is not to say he was unintelligent. It is possible that he thought by tucking the hips under he was flattening and eliminating the lumbar curve of the spine in his practice and taught this to his students. But this seems extremely doubtful given his understanding of the body, mind, and combat science.

   If Wang saw his students with their hips tucked upward, he probably would have corrected them immediately given how inefficient it is for combat. It is also very doubtful that Wang would have let his students tuck the hips upward to flatten the lumbar curve given his knowledge about the body. So, why would Wang instruct his students to “tuck under your pelvis?” If some of Wang’s students were swayback as many people are then tucking the hips under would be a way to correct that. This possibly is where the problem lies, not in Wang’s instructions, but in their interpretation through the years. There is no doubt that Wang Xiang-zhai did indeed tell his students to “tuck the hips under.” But there is a considerable difference in tucking the hips under and tucking the hips upward, as is the modern interpretation.

[1] Cheng Man-ch’ing (1985). Cheng Tzu’s Thirteen Treatises on T’ai Chi Ch’uan, pp 96-97