Changing angle changes everything: Whenever you are in engaged against a skilled opponent he will adopt a stance that is designed to shut down your ability to attack him FROM YOUR current POSITION. However, if you CHANGE your current position by taking an ANGLE on your opponent, that stance will no longer be as effective at stopping your attacks. Changing your angle relative to your opponent changes things considerably and makes possible what was impossible just a second before. Make a habit of moving to a new angle prior to attacking and you'll soon find that you are breaking through defenses that were previously shutting you out.
