Gyaan Sutra

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.

If he is secure at all points, be prepared for him. If he is in superior strength, evade him. If he is of choleric temper, seek to irritate him. Pretend to be weak, that he may grow arrogant.

- Sun Tzu, on The Art Of War