To pincer means to bring your forearms towards each other in an attempt to squeeze off your opponent's forward attack.Â A pincer motion will compress the shouldersÂ creating a rigid defense.
To be "against the wall" is the opposite of pincering.Â It means to pull your arms away from each other as if you were falling back against a wall and you wanted to cushion yourself by having your completely spread arms hit the wall first, palms to the front.
Pincering and "against the wall" are impulses, they don't need to taken to their complete expression-- the smallest hint of either is a mistake.
Instead of these two, we learn to make a circle with our arms.Â If my opponent attacks from the outside of my circle, I make it bigger.Â My arms don't have to be touching each other but the arc of each arm should be on the same circle as the other arm (they should feel connected).Â The most common defect here would be to push up against the attack instead of just making the circle bigger.Â (This defect will force a reversal from your opponent.)
If my opponent attacks form the inside of my circle, I make the circle smaller.Â The two arcs of your arms can overlap.Â The most common defect with this one is pushing downward, (which will also cause a reversal).
Once the technique is mastered the opponent attacks with one arm inside the circle and one arm outside the circle.Â So that you have to create two circles (arcs or partial rings really).Â Then you add turning in the kua (hip region).
Once these techniques have been internalized, it becomes much easier to trust the circle.Â An attack in which you can feel your opponent's jin or power, can be stopped by keeping and changing the circle.