The young man in the video does what most people do when trapped. They give up! ! ! If he would follow the drill we use in our lineage, he would not have gotten hit. Once the arms are trapped (in the video, right hand over left, being held at the wrist), he should raise his elbow, shift using his right hip, and perform Quan sao (left tan and right bong sao), driving forward towards his opponent. Because the arms are on ball and socket joints (the shoulder joints), it is almost impossible for anyone to prevent you from moving your arms in another direction, thus allowing you to perform a bong or tan sao, or just about any direction you want. Also, the young man does not maintain his immoveable elbow position, thus the reason he is trapped.
And lookig back at the video, the gentleman in the blue shirt gave up the position too soon. From the way the young man attacked with his punch, the guy in the blue shift could easily have done a tan sao or biu sao instead of bong and gotten an immediate strike rather than delay it with 2 extra hand motions. But then I quess he wouldn't have been able to demonstrate one of the possibilities of using bong sao.
There are some problems with the demo , that's for sure , but as a basic idea of how we apply a Bong Sau against a straight punch , it is ok.
As you have pointed out , the demo should have explained that the only reason we are applying the technique at all is because we have tried to intercept his punch and strike through , but we have been met with a greater force and so we are obliged to convert that strike into a Bong Sau.
The other thing that I would do differently is to have the attacker charging in like a freight train in a more street assault type of fashion instead of in a Wing Chun stance and guard and attacking like a limp noodle.
Wing Chun vs Wing Chun demos kind of irritate me to be honest , I'm only really interested if it is random Chi sau sparring.
If he had attacked in the manner I prescribed , there is no chance for him to counter because I would either strike straight through or because of the amount of force coming in I would pivot causing the attacker to be shunted to the side and off balance , hit in the throat end of story.
But because it's a Wing Chun vs Wing Chun type scenario , they've tried to get a bit fancy with the counter and the re-countering , and as we all know there are multiple techniques from Chi Sau that can be applied to counter that initial Bong Sau and strike.
The simplest of which is to do exactly the same thing back to him , which then becomes something similar to the familiar lap sau drill.
But getting back to the initial movement you are 100% correct he should have tried to strike through , because even if you don't get through it actually makes the Bong Sau more effective as you get forward force into the wrist contact which keeps it there and stops the punch sliding up your arm.
It also causes the opponent to feel more force coming in at him and as a reaction he puts more force on and commits more of his bodyweight which in turn gives you more of a dramatic effect in off balancing him with your pivot.
So yeah the demo could have been a lot better in my opinion , but to illustrate the basic mechanics of the Bong Sau against a straight punch if you haven't been able to get through then it is technically sound.
