Greetings Kal, Chee Fatt, and everyone else,
Kal, thanks for the post. After I read it, I realized that I had missed your previous one (edited 04-06-2005).
One thing that I can add to your list for those who may have less familiarity with this type of training than others is that there are means for switching between many of the sets of circles. In this way, there are quite a lot of options for training in a challenging way that does not involve completely unstructured activity or entirely competitive pushing.
Another thing I wanted to mention for those who may not train in this way is that the exercises themselves require a high degree of external detail that is comparable to what is done for postures in the form. In other words, it is not a matter of simply looking at a general pattern and then doing what one likes. This is one of the reasons why this type of training requires some foundation from practice of the form.
At the same time, the object of this "circle training" is not to pay attention to oneself, but rather to one's partner, which necessarily requires a much greater degree of variation and flexibility than is generally practiced overtly in the form. The circles are merely an external manifestation of something that should be going on internally. Pushing with one person is not the same as pushing with another. Even pushing with the same person from one day to the next can be quite different.
Another principle is that although there are applications, counters, and counters to counters that can be practiced in many combinations of the circles, there is neither a mechanical application of postures nor total freedom to do whatever one wants. Some things make more sense at some times than at others. There are even some potential circles that are not trained. Understanding what makes sense and where is part of what constitutes learning to "interpret/understand energy."
Also, even if one applies a counter against an application, someone with a high enough level can simply shrug off the counter and continue with the original application with only slight modifications. In other words, the applications do not work by themselves or in an absolute fashion.
A good practitioner can change quite a lot with only minimal movement if he or she has a good understanding of energy usage. In fact, this "struggle" can take a few seconds to play itself out as both practitioners play with full and empty and fight over how the energy will flow. This fact means that overemphasizing a repertoire of "applications" and "counters" to the detriment of understanding fundamentals is not a good idea.
I like what you said about points of contact. I think this is a more sensible approach than worrying about whether one is on the inside or outside or whether one is attacking one or two arms.
<font face="Verdana, Arial" size="2">I find open-hand is much harded than crossed-hand but probably because I am new at it.</font>
I do not think this is just your experience. Open-hand is harder since there is no obvious way to coordinate the hands, except in the simple symmetrical circling. It maybe easy to intuit how one would apply An (Push) with "open hands," but I do not think it is at all obvious how one would apply Lu, Ji, or Peng without help from a teacher.
<font face="Verdana, Arial" size="2">Friends practising Yiquan told me one of the criteria in open hand is not to allow each hand to cross centerline</font>
I have read a similar principle with respect to Wu/Hao Style, but not with respect to Yang Style. I have some doubts about whether it would apply, given other requirements. I am curious about what others think.
<font face="Verdana, Arial" size="2">waist is continuously turning left and right following the hands</font>
I wonder if we are talking about different exercises. I believe that most of the open-hand circling involves symmetrical movements that require no waist turns at all. When one is allowed free movement that includes asymmetrical movement and waist turns, practically every combination will occur. As far as I am aware, the waist should lead the movement, but there is no fixed relationship between any of the joints.
<font face="Verdana, Arial" size="2">Do not allow opponents hand to touch the body. I think there is logic in it.</font>
I think I see your point. This is an issue you mentioned before. I know that one of the reasons that Yang Zhenduo and Yang Jun stress leaving space under the armpits is to avoid the opponent trapping your arm against your body and being able to issue energy.
On the other hand, I think that the Association training stresses that body contact may occur and that one should not fall into a habit of "resisting" to avoid it. Instead, one should be able to apply elbow and body techniques to make sure that contact to one's body is not the end of the story, but just one more challenge in returning the energy back to the opponent. At a high level, one should also have enough Peng energy at any point in the body so that one can issue even with one's body into the opponent's striking arm.