Do not press an enemy at bay.

What is essential in war is victory, not prolonged operations.

All wars are won or lost before they are ever fought.

Other conditions being equal, if one force is hurled against another ten times its size, the result will be the flight of the former.

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.

Hence that general is skilful in attack whose opponent does not know what to defend; and he is skilful in defense whose opponent does not know what to attack.

The enemy's spies who have come to spy on us must be sought out, tempted with bribes, led away and comfortably housed. Thus they will become double agents and available for our service. It is through the information brought by the double agent that we are able to acquire and employ local and inward spies. It is owing to his information, again, that we can cause the doomed spy to carry false tidings to the enemy.