Most players who slice only have a vague idea of why they do so. Some think it's due to their swing path or their release, and some even blame their equipment. The angle of the clubface is an element they often overlook. However, the simple fact is that if a shot moves left to right, you can be sure the clubface is open at impact. A great way to make sure the clubface isn't open at the moment of truth is to get your left forearm to rotate through impact.
To see the correct rotation, try this simple drill using your watch. Turn your watch so the face is on the underside of the wrist of your lead arm (the left arm for right-handed golfers, the right arm for left-handed golfers).
Keep your lead elbow a couple of inches from your side and rotate your forearm so you can see the entire face of the watch. The left wrist should be flat. This should help you visualize the proper rotation in your swing and also prevent you from flipping the club with your wrists at impact.
If you don't rotate the clubface at all, the face of the watch remains pointed at the ground. During your swing, this incorrect movement results in the open clubface that causes a slice. If you try to rotate with your wrist and not your forearm, you won't see the entire face.
Do this drill with your lead arm alone before practicing with both hands on the club. Continue to work on this movement until you see the watch face consistently, and your slicing woes will disappear for good.
Nick Kumpis, PGA, teaches at Pelican Hill GC in Newport Coast, Calif.