《百战奇略·第五卷·奇战》
大凡战争中所说的用 奇 ，指的是进攻敌人所无防备之处，出击敌人所未意想之时。
凡战，所谓奇者，攻其无备，出其不意也。
The term 奇 （the unexpected） employed in warfare commonly refers to attacking your opponent where he is unprepared and at a time when he least anticipates it.