1. Don't Overuse the Elbow
With practice, the second and third set elbow movements become easy ways to launch an attack against a weak opponent. They can be used to directly strike the opponent or to trap the opponent's arms. These techniques become so natural that they become overused. There is a disadvantage to using the elbow too much. It invites or allows the opponent to get too close to apply a neck pulling hand. It also allows the opponent to get to your side.
2. Off Balance when Hitting
In some instances the opponent can lay a trap by grabbing one of your arms and waiting for you to punch with the other. When you punch he applies an inside Fook sau and immediately chops your neck. It is difficult to defend against the chop. There are several solutions to this situation. One is to use the second set slanting punch. This does not leave your center exposed and allows you to chop the opponent with the same hand. Another solution is to never punch without applying (Garb Lik) or the combined strength of two hands. You use one hand to punch and the other to off balance the opponent. Other solutions also exist.
3. Keep the Elbow in the Center
In most Wing Chun techniques, the elbow is kept fixed in the center of the four quadrants of the body. If a straight line attack comes to the center of your body, the time to intercept the attack or to recover from a mistake is minimized if the elbow is centered. If the opponent's elbow is not in the center, it is very easy to attack when in close contact. The first set and the sticking hands training all emphasize putting the elbow in the center. Many people are not at first flexible enough to touch the elbows together. Various flexibility exercises exist which help. If you cannot put the elbow in the center, you can compensate with quicker movements or body shifting. The Bong sau is an exception to the elbow in the center concept; however, the Bong sau is always immediately changed to an elbow centered technique.
4. Chi not at the Wrist
In the sticking hands training, sink the stance, keep the head up and keep the elbows low. Let gravity do some of the work. There is a saying, "The Chi should not be at the end of the wrist." What this means is that the force concentration or stress should be at the elbow. If your force concentration is at the wrist, then changes, attacks and the detection of attacks will all be too sluggish. There is also a saying, "Let your Chi flow." If you stand with your hip out, your Chi (stress or energy concentration) is concentrated in the curve of your lower back. Lower back pain results, which in turn produces a stiffening of the upper arms. If you have problems in handling force or in changing quickly, look for faults in where your force is concentrated.
5. Resist then Let Go
A tactic in Wing Chun is to mirror the opponent's force, then suddenly allow the opponent's force to come but not as he intended. For example, you have a left high Bong sau and a right low Fook sau. The opponent has a right high Fook sau and a left level Tan sau. If the opponent's high Fook sau presses down with a lot of force, you resist up and then suddenly let the opponent have his way by letting your left hand drop into a Gum sau (pressing hand) while punching with your right hand at the same time. The saying that matches this action is, "Let the opponent go where he wants to go." This principle is used quite often in many other circumstances as well. For example, when the opponent presses your stick with his stick in the high position, you press back, then suddenly release the force and hit low. If the opponent pushes you, push back and then shift and pull the opponent off balance. All of these actions are of a very instantaneous nature.
The Wing Chun Kung Fu Digital Library