A Chinese musical instrument, possibly the oldest still in popular use today, invented over two thousand years ago. It is a string instrument, however, its sound is very different from Western string instruments such as violin and viola, due to its snakeskin resonating box.

The erhu only has two strings compared to four for Western string instruments. The instrument is very simple compared to violins, because it lacks a backboard, and the strings are freestanding, giving the musician much more freedom for vibrato. Violinists, especially newbies, are constrained by the fingerboard under the strings (plus the fact that the left hand is twisted backwards), the erhu has a much more natural feel to it.

Despite its small size, the erhu is played vertically, like a cello. It has been used in combination with Western instruments to produce an East-West fusion type of music, with fairly good results.