The following drills are for the purpose of developing Peng Jin. Peng is ward off. Jin is issuing power. In order to use taiji for self defense this teaching is essential. It teaches the practitioner how to issue power from the "Eight Gates" of tai chi, the four cardinal directions of the circle and four corners of the square of the tai chi form. Peng/ward off, Lu/roll back, Chi/press, An/push, Chou/elbow attack, Lieh/split, Tsai/pull down,, and Kao/shoulder strike. They can be practiced as a group or individually.
Generally this is referred to as peng jin training. Peng is also used to describe an internal springlike quality of taiji, and this title deals with jin or power issuing training of all eight gates not just peng or ward off. These drills isolate each of the eight jins for practicing. In addition to self defense these exercises are very useful for push hand practice.