War is a matter of vital importance to the state; the province of life or death; the road to survival or ruin. It is mandatory that it be thoroughly studied.

The rising of birds in their flight is the sign of an ambuscade. Startled beasts indicate that a sudden attack is coming.

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.

Appraise war in terms of the fundamental factors. The first of these factors is moral influence.

Invincibility is in oneself, and vulnerability is in the opponent. Invincibility is a matter of defense, vulnerability is a matter of attack. Therefore skillful warriors are able to be invincible, but they cannot cause opponents to be vulnerable. That is why it is said that victory is discerned and not manufactured.

The control of a large force is the same principle as the control of a few men: it is merely a question of dividing up their numbers.

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.