In the practical art of war, the best thing of all is to take the enemy's country whole and intact; to shatter and destroy it is not so good.
Sun TzuSomeone unfamiliar with the mountains and forests cannot advance [the team]. One who does not employ local guides cannot gain the advantage.
Sun TzuHence the saying: If you know the enemy and you know yourself, your victory will not stand in doubt; if you now Heaven and you know Earth, you may make your victory complete.
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 Tzu