When the legendary Master Wu Chian Chuan taught Tai Chi to Grand Master Young Wabu, Wu taught him the methodology of cultivating neigong through "Internal Discipline". Wu learned the Tai Chi from his father who learned from the Yangs—without alteration (see FAQ). The Yangs learned the art from the Chens. Internal Discipline should be a common thread through all the classical tai chi forms. And is of particular importance when one wants to develop the full health benefits of Tai Chi and to learn martial arts applications of Tai Chi.
"Internal Discipline": That which directs Internal Energy. Internal Energy: is that which mobilizes Internal Motion. Internal Motion: That which is mobilized by Internal Energy.
Internal Discipline enables you to initiate movements from the internal core of the body (the abdomen and back) rather than from the external parts of the body (the limbs), and cultivates and mobilizes your internal energy for health benefits and martial arts applications.
Classical Tai Chi: "The art of Internal Motion that is mobilized by Internal Energy which is directed by Internal Discipline"