出其不意攻其不備 [ㄔㄨ ㄑㄧˊ ㄅㄨˋ ㄧˋ ㄍㄨㄥ ㄑㄧˊ ㄅㄨˋ ㄅㄟˋ; chu1 qi2 bu4 yi4 gong1 qi2 bu4 bei4] catch an enemy off guard with a surprise attack (idiom, from Sunzi's Art of War 孫子兵法) ◄ ►