西漢前期的董仲舒，
對孔孟學說有研究。
景帝封他為博士，
班固《漢書》記緣由。
仲舒讀書很用功，
整天關在屋裏頭。
三年不曾出門去，
房前菜園也不瞅。
何時皇室對他才尊重？
那是在武帝劉徹即位後。
漢武帝常請他提建議，
董仲舒議論頗深透。
他認為漢朝繼秦而建立，
秦朝的製度已腐朽。
這好比琴上弦索已陳舊，
不換新弦難彈奏。
施政的方針也一樣，
改革不可稍停留。
琴弦該換不更換，
琴師的技巧再高也難彈奏。
應當改革不改革，
政治家想幹出政績不能夠。
“改弦更張”作成語，
常比喻用新的方針政策代陳舊。
政治上的重大改革也可比，
唯改革社會才前進不退後。
Change the String on the Banjo
Dong Zhongshu，in the Western Han Dynasty（206B。C。—24A。D。），made a very good study of Confucius'and Mencius'Doctrines。Emperor Jing honoured him as a doctor，about which Bangu's“History of Han”has given accounts。
It is said that he studied very hard，and shut himself in his room day and night。For three years he had not gone out of his room，and paid no heed to the garden in front of his house。When did His Majesty honour him？Not until Emperor Wu，Liu Che had e to the throne。
Emperor Wu often asked him to give him some advice，and Dong's account was deep and of great significance。He said that Han had derived from Qin，but Qin's system had rotted through。This was just like an old banjo whose strings had worn out。You could not play it any more unless you changed the strings。An administrative policy is the same way，so you must make a reform without delay。If a banjo's strings need changing，but you won't change them，no one can play it well，no matter how skillful a person might be。If you should reform but you won't reform，a good politician can't make any achievements even if he wants very much to do so。
“Change the Strings on the Banjo”as an idiom，usually implies a new policy has taken the place of the old one it can also refer to a great reform in politics，and only in this way can the society make progress。