A military operation involves deception. Even though you are competent, appear to be incompetent. Though effective, appear to be ineffective.

The nature of war is constant change.

The military has no constant form, just as water has no constant shape - adapt as you face the enemy, without letting them know beforehand what you are going to do.

A clever general... avoids an army when its spirit is keen, but attacks it when it is sluggish and inclined to return. This is the art of studying moods. Disciplined and calm, he awaits the appearance of disorder and hubbub among the enemy. This is the art of retaining self-possession.

The difficulty of tactical maneuvering consists in turning the devious into the direct, and misfortune into gain.

Therefore, just as water retains no constant shape, so in warfare there are no constant conditions.

By altering his arrangements and changing his plans, the skillful general keeps the enemy without definite knowledge. By shifting his camp and taking circuitous routes, he prevents the enemy from anticipating his purpose. At the critical moment, the leader of an army acts like one who has climbed up a height and then kicks away the ladder behind him.