四面楚歌 - To Hear the Songs of Chu from Four Sides

Yesterday I came across this chengyu in an anime about a calligrapher finding himself (don't know, only watched one episode) and I instantly got curious, because from my studies I could recognise all the characters, I could even translate them literally, but I had no idea how they all add-up into what the translation the translator decided to give, which was "surrounded by enemies on all sides". 

After a quick search on zdic I found out why this was, and with a bit of work I realised that indeed it was yet another one of the thousands of chengyus any student of Chinese (be it classical or modern) will encounter. 

The expression itself is used when describing an utterly hopeless and/or hostile situation. The story takes place in 202 BC during the Chu-Han Contention (楚漢相爭), where the Tyrant/Hegemon-King (霸王) Xiang Yu's army was besieged at Gaixia (in what is today Anhui province).

Below is my attempted translation of the story behind the expression, from Sima Qian's Records of the Grand Historian (plus some of the text I accidentally copied over from Baike Baidu but I'm not going to throw it away because I worked on it, and I think it gives a nice framing to the short story.)

四面楚歌
To Hear the Songs of Chu from Four Sides 

司马迁《史记·项羽本纪》：“项王军壁垓下，兵少食尽，汉军及诸侯兵围之数重。
Sima Qian in the biography of Xiang Yu in the Records of the Historian wrote:
King Yu fortified Gaixia, but his troops were few, and supplies consumed. The lords and troops of Han that surrounded him were two-fold superior in numbers. 

夜闻汉军四面皆楚歌，项王乃大惊，曰：‘汉皆已得楚乎？是何楚人之多也。’”
During the night the songs of the people of Chu could be heard from the four directions of the Han armies, and in great distress King Yu asked: "Have the hans already conquered all of Chu? These Chu-folk are very great in number!" 

后世据此典故引申出成语“四面楚歌”。
Later generations derived the chengyu "To Hear the Songs of Chu from Four Sides" from this classical story.