At the end of the Qin Dynasty(221-206 B.C.) the State of Chu and the State of Han fought for control for the country. Xiang Yu, the king of Chu, was besieged（包圍） at a place called Gaixia by the Han army led by Liu Bang. Xiang Yu was in a desperate situation, with little food and only a few soliders. 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.
This idiom is used metaphorically to mean to be in a helpless and critical situation, surrounded by the enemy on all sides.

項(xiàng)羽和劉邦原來(lái)約定以鴻溝（在今河南榮縣境賈魯河）東西邊作為界限，互不侵犯。后來(lái)劉邦聽(tīng)從張良和陳平的規(guī)勸，覺(jué)得應(yīng)該趁項(xiàng)羽衰弱的時(shí)候消滅他，就又和韓信、彭越、劉賈會(huì)合兵力追擊正在向東開(kāi)往彭城（即今江蘇徐州）的項(xiàng)羽部隊(duì)。終于布置了幾層兵力，把項(xiàng)羽緊緊圍在垓下（在今安徽靈璧縣東南）。這時(shí)，項(xiàng)羽手下的兵士已經(jīng)很少，糧食又沒(méi)有了。夜里聽(tīng)見(jiàn)四面圍住他的軍隊(duì)都唱起楚地的民歌，不禁非常吃驚地說(shuō)：“劉邦已經(jīng)得到了楚地了嗎？為什么他的部隊(duì)里面楚人這么多呢？”說(shuō)看，心里已喪失了斗志，便從床上爬起來(lái)，在營(yíng)帳里面喝酒，并和他最寵愛(ài)的妃子虞姬一同唱歌。唱完，直掉眼淚，在一旁的人也非常難過(guò)，都覺(jué)得抬不起頭來(lái)。虞姬自刎于項(xiàng)羽的馬前，項(xiàng)羽英雄末路，帶了僅剩兵卒至烏江，最終自刎于江邊。
以后人們就用“四面楚歌”這個(gè)詞，形容人們?cè)馐芨鞣矫婀艋虮破?，而陷于孤立窘迫的境地。凡是陷于此種境地者，其命運(yùn)往往是很悲慘的。例如某人因經(jīng)常與壞人為伍，不事生產(chǎn)，游手好閑，但后來(lái)卻被那些壞人逼迫得無(wú)以為生，而求助于別人時(shí)，別人又因他平日行為太壞，絕不同情理睬，這人所處的境地便是“四面楚歌”。
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