Appear weak when you are strong, and strong when you are weak.

He will win whose army is animated by the same spirit throughout all its ranks.

Someone unfamiliar with the mountains and forests cannot advance [the team]. One who does not employ local guides cannot gain the advantage.

Therefore I say: know the enemy and know yourself; in a hundred battles you will never be in peril. When you are ignorant of the enemy but know yourself, your chances of winning or losing are equal. If ignorant both of your enemy and of yourself, you are certain in every battle to be in peril.

If you are situated at a great distance from the enemy, and the strength of the two armies is equal, it is not easy to provoke a battle, and fighting will be to your disadvantage.

The sovereign must have full knowledge of the activities of the five sorts of agents. This knowledge must come from the double agents, and therefore it is mandatory that they be treated with the utmost liberality.

Now a soldier's spirit is keenest in the morning; by noonday it has begun to flag; and in the evening, his mind is only on returning to camp.