The art of war speaks of "moving later yet arriving first", meaning that the other side moves first and one moves after, yet arrives first; and of "avoiding strength to strike weakness", meaning that one does not meet the other's strong point head on but strikes at its weak one. Tai Chi Principles puts these two sayings into how the body uses force and how it contends with another person.
Around the Ming-Qing transition taijiquan arose at Chenjiagou in Wen County, Henan. It is generally credited to Chen Wangting of Chenjiagou, who combined his family's boxing, breathing and guiding exercises, and yin-yang theory to create it.
In the mid-to-late Qing, Yang Luchan brought Chen-style taijiquan to Beijing, where it gave rise to the Yang style and other schools, and taijiquan spread widely.
On this account, family boxing, breathing and guiding exercises and yin-yang theory are its three sources, and the ideas of the art of war are the principles it borrows.
Tai Chi Principles is the class in the chapter on Strategies on the boxing method. It covers how the military ideas of "moving later yet arriving first" and "avoiding strength to strike weakness" are carried over into the force of the body and into sparring. The common account is that Chen Wangting created taijiquan around the Ming-Qing transition and that Yang Luchan brought it to Beijing in the mid-to-late Qing, where it gave rise to several schools.
