Without preparedness superiority is not real superiority and there can be no initiative either. Having grasped this point, a force which is inferior but prepared can often defeat a superior enemy by surprise attack. We say an enemy on the move is easy to attack precisely because he is then off guard, that is, unprepared.
优势而无准备，不是真正的优势，也没有主动。懂得这一点，劣势而有准备之军，常可对敌举行不意的攻势，把优势者打败。我们说运动之敌好打，就是因为敌在不意即无准备中。
Original text (Chinese)