Therefore I say: know the enemy and know yourself; in a hundred battles you will never be in peril. When you are ignorant of the enemy but know yourself, your chances of winning or losing are equal. If ignorant both of your enemy and of yourself, you are certain in every battle to be in peril.

The art of using troops is this: ......When ten to the enemy's one, surround him; ......When five times his strength, attack him; ......If double his strength, divide him; ......If equally matched you may engage him; ......If weaker numerically, be capable of withdrawing; ......And if in all respects unequal, be capable of eluding him, ..........for a small force is but booty for one more powerful.

So a military force has no constant formation, water has no constant shape: the ability to gain victory by changing and adapting according to the opponent is called genius.

If your enemy is secure at all points, be prepared for him. If he is in superior 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 his 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.

Use humility to make the enemy haughty. Tire them by flight. Cause division among them. When they are unprepared, attack and make your move when they do not expect it.