Whoever is the first in the field and awaits the coming of the enemy will be fresh for the fight... Therefore the clever combatant imposes his will on the enemy... By holding out advantages to him, he can cause the enemy to approach of his own accord; or by inflicting damage, he can make it impossible for the enemy to draw near.
Sun TzuFrom a position of this sort, if the enemy is unprepared, you may sally forth and defeat him. But if the enemy is prepared for your coming, and you fail to defeat him, then, return being impossible, disaster will ensue.
Sun Tzu