We practice Professor Cheng Man-ch'ing's "simplified" 37 posture Yang-style form. The three pillars of our study are Form,Sensing Hands, and Sword.
Long River Tai Chi Circle has branches in the US and Europe.
It was flexibility that was his (the professor's) tool. However, not a flexibility that results from everything being disjointed.
The key is to combine the ideas of one-piecedness with flexibility, creating Taichi.
In the classics much is made of the quality of Taichi being like a whip, rather than a stick.
It's relevant that a whip is still "one-pieced" but it is not rigid. It combines a unified chi with complete flexibility.
...we should remember that when we say "Relax," we are also saying, "Be loose."