The fundamental swing plane is very important as we progress around the swing map. You know it joins the fundamentals of leverage and balance and blends in together for maximum efficiently, both in trajectory and quality of strike and also the swerve that you put on the ball. Let me just summarize that again. As you look from the address position, if the club is traveling too much from in front of you or too steep, which is a common error, the likelihood is that you are going to strike the ball on the top or the ground to the target side of the ball. This is a poor quality strike, so many golfers will react to this strike by trying to come down to find the bottom of the golf ball. That route provides very poor contact and inconsistency. Other golfers have the swing plane coming too much from the inside. Their likelihood is that they are going to hit the ground in front of the ball, so their instinct says to come up and they hit the top of the ball, once again, poor strike consistency. So swing plane blends together the balance and leverage fundamentals, but in itself it can control also the swerve or direction that you see on the golf ball. For instance, if my club comes too much from the inside track, too shallow or too flat, the ball will most likely want to go out to the right. From this position I react by trying to flip the club over. Trying to make sure that the ball does not go off to the right by making the face tell it to come more to the left. One interesting problem that we have seen over the years is an inside track with the clubface flicking over very quickly and actually sending the ball over to the left, which completely confuses the ballflight law people. Of course the reverse is also true. When the club is too much in front of you, what happens now? You do not want the ball to go to the left so you start to open up the clubface. In the extreme form the face is so open that the ball goes off to the right even though the swing plane direction was over to the left. Once again confusing those people who just operate on the idea that the ball starts in the direction of the swing and swerves because the clubface. Sometimes the clubface overrides the plane and that is important knowledge when you are trying to diagnose the flight of the ball. Of course not all golfers can get the plane clear in their mind by practicing in front of a mirror. A very simple exercise that you can have to understand your own swing plane is to practice from the delivery position to understand that when the club is in plane with the right forearm pop it backwards and forwards so that you can feel where the club should be approaching from as it comes into impact. Indeed if you do this exercise you can even hit some shots. With a little bit of practice you will understand where the swing plane should come from and you will not be guilty of too much from behind or too much from in front.