It is only one who is thoroughly acquainted with the evils of war that can thoroughly understand the profitable way of carrying it on.

All war is based on deception.

Keep their friends close and their enemies closer.

There are five dangerous faults which may affect a general: recklessness, which leads to destruction; cowardice, which leads to capture; a hasty temper, which can be provoked by insults; a delicacy of honour, which is sensitive to shame; over-solicitude for his men, which exposes him to worry and trouble.

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.

First learn to become invincible, then wait for your enemy's moment of vulnerability.

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