The height of strategy, is to attack your opponent's strategy.

No ruler should put troops into the field merely to gratify his own spleen; no general should fight a battle simply out of pique.

Like the sun and moon, they end but to begin anew; like the four seasons, they pass away to return once more.

Confront them with annihilation, and they will then survive; plunge them into a deadly situation, and they will then live. When people fall into danger, they are then able to strive for victory.

When you are ignorant of the enemy but know yourself, your chances of winning or losing are equal.

When one treats people with benevolence, justice and righteousness, and reposes confidence in them, the army will be united in mind and all will be happy to serve their leaders.

Hence the saying: If you know the enemy and you know yourself, your victory will not stand in doubt; if you now Heaven and you know Earth, you may make your victory complete.