Unless you know the mountains and the forests, the defiles and impasses, the lay of the marshes and swamps, you cannot maneuver with an armed force. Unless you use local guides, you cannot get the advantages of the land.

Spies cannot be usefully employed without a certain intuitive sagacity; (2) They cannot be properly managed without benevolence and straight forwardness; (3) Without subtle ingenuity of mind, one cannot make certain of the truth of their reports; (4) Be subtle! be subtle! and use your spies for every kind of warfare; (5) If a secret piece of news is divulged by a spy before the time is ripe, he must be put to death together with the man to whom the secret was told.

Be the first to seize intersecting ground, that is ground which lies the intersections of borders or intersections of main thoroughfares of commerce and travel. Your occupation of it gives you access to all who border it and all who would covet it. On intersecting ground, if you establish alliances you are safe, if you lose alliances you are in peril.

The relative size of your force as against that of your adversary is by itself of no consequence. What controls is the relative size of your force at the point where you join in battle. You can strike with the few and be many if you strike your adversary in his gaps. Seek out places where the defense is not strict, the place not tightly guarded, the generals weak, the troops disorderly, the supplies are scarce and the forces are isolated.

It is the rule in war, if ten times the enemy's strength, surround them; if five times, attack them; if double, be able to divide them; if equal, engage them; if fewer, be able to evade them; if weaker, be able to avoid them.

If asked how to cope with a great host of the enemy in orderly array and on the point of marching to the attack, I should say: "Begin by seizing something which your opponent holds dear; then he will be amenable to your will." Rapidity is the essence of war: take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots.

As water has no constant form, there are in war no constant conditions.

Who does not know the evils of war cannot appreciate its benefits.

Generally in war the best policy is to take a state intact; to ruin it is inferior to this.