Ping Gong of Jin commissioned the making of a stringed instrument. However, all the strings were of identical thickness, with no distinction between the large and small strings. Once completed, Ping Gong ordered Shi Kuang, the court musician, to tune it. Shi Kuang labored for an entire day but could not produce a proper melody.
Ping Gong blamed Shi Kuang for his incompetence. Shi Kuang explained: "The large string of an instrument is like the ruler of a state, and the small strings are like his ministers. Each has its own distinct role. Only through mutual coordination can they create proper temperament; only through order can they produce harmonious and pleasant music. Now, with no difference in size between the strings, their essential system and regularity are destroyed. How can I possibly tune such an instrument?"