偷梁换柱　

◎ 偷梁换柱 tōuliáng-huànzhù

[steal the beams and pillars and replace them rotten timber-perpetrate a fraud] 意为玩弄手法、暗中改换内容,以达到蒙混欺骗的目的。军事上是说与别的军队联合作战时,暗中抽换其主力,使作战失利,以乘机吞并之