  To Lower the Banners and Silence the Drums 偃旗息鼓

  In the Three Kingdoms Period, during a battle between Cao Cao and Liu Bei, the latter ordered his generals Zhao Yun and Huang Zhong to capture Cao Cao's supplies. Cao Cao led a large force against Zhao Yun, who retreated as far as the gates of his camp. There, he ordered that the banners be lowered and the war drums silenced, and that the camp gates be left wide open. Zhao Yun then stationed his troops in ambush nearly. When Cao Cao arrived and saw the situation, he immediately suspected a trap and withdrew his forces. 
  三国时代，一次曹操与刘备交战。刘备命令大将赵云、黄忠去抢夺曹操的粮食。曹操带领大军追赶赵云。赵云边打边退，一直退到营寨前，叫士兵打开营门，放倒军旗，停止擂鼓，在营外设好埋伏。曹军追到，看到这种情景，怀疑有埋伏，就撤退了。

  This idiom is nowadays used to indicate metaphorically halting an attack or ceasing all activities.
  "偃旗息鼓"这个成语现在用来比喻停止攻击或者事情中止。