Hostile armies may face each other for years, striving for the victory which is decided in a single day. This being so, to remain in ignorance of the enemy's condition simply because one grudges the outlay of a hundred ounces of silver in honors and emoluments, is the height of inhumanity.

Every battle is won before it is fought.

Invincibility lies in the defense; the possibility of victory in the attack.

Opportunities increase as they are taken.

If not in the interests of the state, do not act. If you cannot succeed, do not use troops. If you are not in danger, do not fight.

If we wish to fight, the enemy can be forced to an engagement even though he be sheltered behind a high rampart and a deep ditch. All we need do is attack some other place that he will be obliged to relieve.

Against those skilled in attack, an enemy does not know where to defend; against the experts in defense, the enemy does not know where to attack.