Wu Hao (武式郝家拳) is one of the 5 main branches of Tai Ji. It is one of the least known systems, not just in the US but in China as well. Wu Hao style is considered a small-frame form without large movements. Its focus is on achieving internal strength through the development of Qi. 

Gin Yu, Master Liu Jishun, Chao Pang
Santa Barbara Wu Hao Tai Ji Association