Should the enemy forestall you in occupying a pass, do not go after him if the pass is fully garrisoned, but only if it is weakly garrisoned.
Sun TzuThe clever combatant imposes his will on the enemy, but does not allow the enemy's will to be imposed on him.
Sun TzuAs water shapes its flow in accordance with the ground, so an army manages its victory in accordance with the situation of the enemy.
Sun TzuThe 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.
Sun Tzu