Therefore, just as water retains no constant shape, so in warfare there are no constant conditions.
Sun TzuWhen the enemy's envoy's speak in humble terms, but continues his preparations, he will advance. When their language is deceptive but the enemy pretentiously advances, he will retreat. When the envoys speak in apologetic terms, he wishes a respite. When without a previous understanding the enemy asks for a truce, he is plotting. When the enemy sees an advantage but does not advance to seize it, he is fatigued.
Sun TzuThose 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.
Sun Tzu