QUOTE
This principle was applied to many stringed instruments in the middle ages. One easy-to-make and [Image]popular instrument was the "bum fiddle", which was an inflated pig's bladder held tightly against a straight stick with a string, which was bowed. There wasn't a fingerboard as such, so the notes were varied by pressing against the string to tighten it. It had a rough, unmusical sound and the notes weren't particularly easy to control.
UNQUOTE

Similar to the Erhu often called the 'Chinese Violin'.