Sensing the energy in the opponent

It has been a while since I notice how students are powering up when they engage with each other while I am watching from the side without touching them. I am not yet sure how I can tell. Is it their subtle movement, body language or something else? E.g. I can tell if they are pushing from the heel or toes, if they are powering up with a back muscle, at the shoulder, or with the kua. This information is useful in identifying the fixed dot in the opponent's body. It allows me to help the students understand their bodies, and what they are actually doing. They ask me how I can tell, however at this point, I honestly don't know how I know, I just do. It just seems like the energy is running through the body.
Today, I was teaching a student how to kick with heel. The focus was to stretch the back of the leg and not let the energy get stuck on the knee. I was telling the student the difference between the proper and non-proper ones. I realized that I was not using my eyes or any touch to tell if she was stretching or not. The leg might be extended but not necessarily stretched. We did a test with me looking a way to see if I could tell if she was stretching or not. We repeated the test a few times, and somehow I could tell. Was I using some sort of sound? I was not sure, I just felt it in my body somehow. This was written for the sake of recording the incident.
One of the ways to learn to locate the fixed dot is to put some pressure on the opponent and see how he reacts to it, e.g. how he resists it. The same person tends to react the same way, the more you work with a person, the more you are used to his actions and can anticipate what he will do. The more people you work with, the more developed the skill. It eventually helps in dealing with you have never met before.

Drilling Down

This week, I found myself able to drill the opponent down causing him to eventually fall vertically to the ground.  The particular exercise was about me putting my right hand on the opponent's right shoulder, and my right thigh behind the opponent's left thigh. I pulled my elbow down his back and towards my right kua to lock the opponent (This would cause a compression on the opponent's spine). I realized a fixed dot at the opponent's left ribs. I opened my right kua upwards, and ended up taking out the space in the opponent. The result was that the opponent left leg would fly straight out, and I would be like drilling him straight to the ground with the original fixed dot going straight down with no tossing. Note that it was important not to thinking about rotating myself or the opponent at all. The rotation was only the result, and not my action. When I opened my kua, I opened it with a straight aim in a particular direction tightly in front of the fixed dot on the opponent's front. At the same time, I did a separate stretch tightly behind the fixed dot on the opponent's back. This was just like putting the hands on the stick of a rattle drum in order to spin it. I did the same drill the prior week with the same person. He commented that it felt different this week. He was falling with my action, and it was more crisp. I tried the exercise with a different fixed dot. This time it was on his right ribs. The result was the same. I drilled him down on that axis.  I tried this exercise with another person. Besides doing it by opening the kua as described above, I did it also by stretching the head/neck to the other side of the dot. It was like tipping the lever on the other end of the lever compared to what was done with the kua. I remembered first time creating a similar result a few years ago with Master Chen Zhonghua providing step-by-step verbal instructions on the side. Not until now (9+ years of training), I am able to do it in a controlled/limited manner on my own. Master Chen said training taiji was like boiling water. Water at 30 degrees, 70 degrees, 90 degress, etc is still water (H20 in liquid form), not until it reaches 100 degrees, it would become steam (H20 in gas form) and have fundamental change.  However, we must keep boiling, and not stop the fire.  This is known as huo hou 火候 in Chinese.