You can prevent your opponent from defeating you through defense, but you cannot defeat him without taking the offensive.

Factors in the art of warfare are: First, calculations; second, quantities; third, logistics; fourth, the balance of power; and fifth, the possibility of victory is based on the balance of power.

When strong, avoid them. If of high morale, depress them. Seem humble to fill them with conceit. If at ease, exhaust them. If united, separate them. Attack their weaknesses. Emerge to their surprise.

Bring war material with you from home, but forage on the enemy... use the conquered foe to augment one's own strength.

Of all those in the army close to the commander, none is more intimate than the secret agent.

Opportunities increase as they are taken.

Be where your enemy is not.