It's amazing how many people cannot hit this shot. Keith Wood explains how:
This is actually a good drill for helping get rid of the flip as usually flippers cannot hit a punch properly. It also resembles a 'Mike Bennett drill' as described by Nick Clearwater
As Wood explains, you don't want to close the clubface when hitting a punch because the ball will start off left. But you also have to remember that the ball is likely to draw with the low punch because your angle of attack should be steeper, which makes the horizontal plane go out the right. So if you were to close the clubface, then you are really going to hook it. If you want to hit it straight, swing left. If you want to hit a punch with a fade, swing very far to the left.
The punch is a good shot to learn not only because it helps into the wind, but it's a shot that if you can master can save some shots when you get into trouble. One of the issues with 'ballstrikers' is that they are never used to hitting shots under trees and don't really know what to do when they have this issue.