Sun Tsu: The Art of War said:All warfare is based on deception. Hence, when able to attack, we must seem unable; when using our forces, we must seem inactive; when we are near, we must make the enemy believe we are far away; when far away, we must make him believe we are near. Hold out baits to entice the enemy. Feign disorder, and crush him.
Sun Tsu: The Art of War said:If your enemy is secure at all points, be prepared for him. If he is superior in strength, evade him. If your opponent is tempermental, seek to irritate him. Pretend to be weak, that he may grow arrogant. If he is taking ease, give him no rest. If his forces are united, separate them. If sovereign and subject are in accord, put division between them. Attack him where he is unprepared, appear where you are not expected.
I've studied his texts as well. It's amazing that these fundamental truths held in a 2000+ year old manuscript carry as much weight now as they did when it was written...