  Songs of Chu on All Sides 四面楚歌

  At the end of the Qin Dynasty (BC 221-206), the State of Chu and the State of Han fought for control of the country. Xiang Yu, the king of Chu, was besieged at a place called Caixia by the Han army led by Liu Bang. Xiang Yu was in a desperate situation, with little food and only a few soldiers. At night, the surrounding Han troops started to sing Chu folk songs. Xiang Yu was very surprised at this, and said, "Has Liu Bang occupied the whole of Chu? How can he have drafted so many Chu people into his army?" Then he fled together with the remainder of his forces.
  秦朝末年，楚和汉争夺天下。楚王项羽被汉王刘邦的军队紧紧地围困在垓下这个地方。项羽的兵士已经很少，粮食也没有了，危机万分。夜里，四面包围着的汉军唱起了楚地的民歌。项羽听了，非常吃惊地说："汉军已经全部占领了楚国的土地吗？为什么在汉军中有这么多的人会唱楚歌呢？"说着就从床上爬起来，带着残余的士兵惊慌地逃走了。

  This idiom is used metaphorically to mean to be in a helpless and critical situation, surrounded by the enemy on all sides.
  "四面楚歌"这个成语比喻四面受到敌人的攻击，处于孤立危急的困境。