The Chinese idiom 滥竽充数 (lan4 yu2 chong1 shu4) literally means to pass oneself off as a member of the ensemble.The idiom was first used over 2,000 years ago to describe the behaviour of Nanguo, a subject of the King of the State of Qi.
The King of Qi loved to listen to Yu (ancient wind instruments) played in unison. He regularly employed over 300 Yu players to perform at his court and offered them generous pay and benefits to ensure that he retained the cream of the crop. Nanguo was not well versed in the art of playing the Yu, but he envied the Yu players and wished to enjoy the lucrative benefits they received. So, he went to the court and told the King that he was an excellent Yu player and that he wanted to join the imperial ensemble. The King was very happy to recruit a master Yu player.
During each performance, Nanguo imitated the finger movements of the other players and pretended to play very enthusiastically. The King did not discover that Nanguo was in fact pulling the wool over his eyes and, as a result, was very impressed by Nanguo's performances. Years later the King died and was succeeded by his son who also loved to listen to the Yu. However, the new ruler preferred solo performances and asked each of the players in the imperial ensemble to perform one by one. Nanguo knew the game was up and headed for the hills before it was his turn to perform a solo.
Today, the Chinese idiom 滥竽充数 (lan4 yu2 chong1 shu4) can be used in a derogatory way when referring to someone else ("He is completely lacking talent and should never have been appointed to the post") or it can be used to show modesty regarding one's own abilities ("Although I am in this post, I am not the best or most qualified person to occupy it") . English speakers convery a similar meaning when they say that someone or something is there to make up the numbers.