- B's both hands are free.
- B can borrow A's kneeing force, add his leg pulling force.
- B can borrow A's pulling force, adds his shoulder pushing force.
Here is a similar situation.
This is not in disagreement to Kung Fu Wang. I'm just going into more detail. You will also see B borrowing force as Wang described.
B can only do those things if his stance is strong.. The ultimate truth in all fighting systems is that Balance is always overrides any action, which is why so many systems exploit it. If B cannot maintain balance then there's nothing that B can do to counter. The ultimate strike in all systems is the one that destroys balance, after that it's the one that destroys structure.
The attack that A does destroys balance and breaks structure in that order. B's balance is broken and then his structure is broken as he tries to regain balance. At this pace A is ahead of B. B is performing 1 step behind. He's trying to regain balance as his structure is being broken, which is no good. So B tries to regain structure which is also the moment when A strikes with the knee.
The defensive match must be
A attacks balance = B Defend Balance. This will stop any follow up from occurring .
If the defense if.
A attacks balance - B loses Balance then the series of actions will follow.
A attacks balance - B loses balance
A attacks balance - B corrects balance
A attacks with knee - B corrects structure
A attacks balance - B defends against knee.
The series above shows how B is always 1 step behind. This is the same thing that happens when grapplers take down strikers
Grappler attacks balance - B throws strike
Grappler attacks structure - B tries to regain balance
Grappler controls limbs - B tries to regain structure
Grappler locks joints - B tries to control limbs.
In both example, B is one step behind in his defense. The defense picked is never appropriate for the attack and it starts with that loss of balance.
If B can address the correct defense at the correct time then B can gain the upper hand and then force A to Strike. This what it looks like when B counters
A attacks balance - B defends balance
A attacks structure - B attacks balance.
A tries to regain balance - B - attacks structure
A tries to correct structure - B attacks balance.