These are the six ways of courting defeat - neglect to estimate the enemy's strength; want of authority; defective training; unjustifiable anger; nonobservance of discipline; failure to use picked men.

When you surround an army, leave an outlet free. Do not press a desperate foe too hard.

The clever combatant looks to the effect of combined energy, and does not require too much from individuals. Hence his ability to pick out the right men and utilize combined energy

Subtle and insubstantial, the expert leaves no trace; divinely mysterious, he is inaudible. Thus he is master of his enemy's fate.

If it is to your advantage, make a forward move; if not, stay where you are.

The skillful tactician may be likened to the shuai-jan. Now the shuai-jan is a snake that is found in the Ch'ang mountains. Strike at its head, and you will be attacked by its tail; strike at its tail, and you will be attacked by its head; strike at its middle, and you will be attacked by head and tail both.

All war is based on deception.