"The basic unit of Tai Chi is the circle. Circle, circles, everywhere. The first stage in Tai Chi is relaxing to the point where the upper body is so floppy that strong turns of the waist from a sunk, rooted, bent-legged stance, will fling the arms into either complete or partial circles. Strong, powerful, loaded legs and a fluid waist directing a loose and relaxed upper body. The difficulty with the postures of Tai Chi, stylized as they are – to the point of being highly compromised in many cases, is to connect our main circle to the incoming energy and to get both arms involved in that circle. The circle can be on the horizontal or vertical plane so can connect with the incoming energy from the left, from the right, from underneath or from above. Returning the energy is simply completing the circle.
Relaxation is the key and we initially encourage a flat detachment to cultivate this relaxation. Philosophically this fits with Buddhist/Taoist concepts of non-action and emotional detachment – we may be doing something but it is minimal and devoid of the tensions associated with striving or desire. This is only the first stage, but it is absolutely vital. Without it the student may succeed quite well in the later stages but they won't fully understand or feel or connect to the energy as energy. It should be realized that a student doesn't need to master the first stage before she can proceed onto the next. She just needs to have become so thoroughly infected with interest, and with the need to practice, that success is a foregone conclusion – is just a matter of time."
From the Blog called Tai Chi Heartwork
Ba Gua Zhang (Pa Qua Chang): Walking the Circle