The “Practical Method” of Chen-style Taijiquan developed by Hong Junsheng brings the TaiChi principle into spectacular clarity.
While the forms are given evocative and compelling names such as “White Crane Flashes Wings” and “Part the Wild Horse’s Mane”, the actions which are necessary to perform them are quite simple.
The actions of the upper-body can be reduced to, essentially, two forms. Following the general arc of a circle, the arms are either travelling one way or the other! The Practical Method refers to these as the “Positive Circle” and the “Negative Circle”.
Circular actions of the arm imply motion on both the plane of In/Out as well as the plane of Up/Down. Combined with rotation of the central axis of the body and proper action of the lower-body, these two circular paths account for the entire lexicon of arm actions across all the forms of Taijiquan.
More specifically, the Practical Method asserts that inward action is performed by the elbow (represented by the dots in the illustration above). The elbow is either travelling toward the body from a high, or a low, position. Once the elbow arrives at the body the waist turns (signified by the figure-eight shape) and sets a trajectory for the continued motion of the arm, either on its current course around the circle or reversing course to retrace the circle on which the elbow arrived. Lastly, the hand (shown as an X above) is delievered outward along the circular path in accordance with the trajectory set by the turning of the waist.
The two arms, moving in various combinations along the circular paths described by the Practical Method, need not attend to anything else. The names of postures are merely shorthand and fanciful expressions of very simple directions.