Now this foreknowledge cannot be elicited from spirits; it cannot be obtained inductively from experience, nor by any deductive calculation.

Rapidity is the essence of war.

Attack him where he is unprepared, appear where you are not expected.

So the principles of warfare are: Do not depend on the enemy not coming, but depend on our readiness against him. Do not depend on the enemy not attacking, but depend on our position that cannot be attacked.

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.

Of all rewards none [is] more liberal than those given to secret agents.

To capture an enemies army is better than to destroy it.