It is a doctrine of war not to assume the enemy will not come, but rather to rely on one's readiness to meet him; not to presume that he will not attack, but rather to make one's self invincible.
Those who do not know the plans of competitors cannot prepare alliances. Those who do not know the lay of the land cannot maneuver their forces. Those who do not use local guides cannot take advantage of the ground.
Should one ask: 'how do I cope with a well-ordered enemy host about to attack me?' I reply: seize something he cherishes and he will conform to your desires.