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

Do not engage an enemy more powerful than you. And if it is unavoidable and you do have to engage, then make sure you engage it on your terms, not on your enemy's terms.

If I determine the enemy's disposition of forces while I have no perceptible form, I can concentrate my forces while the enemy is fragmented. The pinnacle of military deployment approaches the formless: if it is formless, then even the deepest spy cannot discern it nor the wise make plans against it.

What enables the wise sovereign and the good general to strike and conquer, and achieve things beyond the reach of ordinary men, is foreknowledge.

And therefore only the enlightened sovereign and the worthy general who are able to use the most intelligent people as agents are certain to achieve great things.

What the ancients called a clever fighter is one who not only wins, but excels in winning with ease.

A warrior who is prepared to fight must also be prepared to die.