Ben Hogan's plane of glass

One Ben Hogan's golf tips was, "Try to imagine you have plane of glass going from the ball to over your shoulders with a hole for your head to poke through. Then, try as you swing consciously try not to break that plane of glass."

This tip is meant to help someone from going "outside-in," which causes a slice.

Watch the video and see how perfectly on a single plane his swing is.