One of the key aspects of Wing Chun and its relatives is pressure.
When dealing with an attack, Boxers and much of MMA and sport related arts focus on defending the strike. Block or catch the punch while holding your ground. The idea is so straightforward it is rarely questioned. Of course, you want to block the strike. The next step is to strike into an opening. Block, holding ground, and look for openings. This can go on for some time.
Wing Chun’s approach is to meet to the strike, which is effectively blocking it, but to also attach to it and put pressure on it – to escort it away. That forward pressure into the attacker aids in shutting them down. It makes it easier to predict or feel what the attacker’s counter will be. In fact, it forces them to counter or at least react.
Forward pressure does not mean merely pushing against the strike or kick. It means moving in against it. Moving closer to the opponent while staying attached to the strike. Like water against a dam, Wing Chun’s forward pressure should be relentless. Strong but never over-committed, it should be a continual burden to the opponent, collapsing their structure and limiting their responses.
If a strike is simply blocked, the attacker’s structure is not affected. Whatever plan they had for a next move, the continuation of a combination, is freely available to them. However, when the strike is blocked with forward moving intent, their current structure becomes compromised. Their previous plan or combination must change or proceeds in a feeble manner.
Boxers look for an opening. Wing Chun’s forward pressure creates one.