Concerning the types of Kokyu, four-stringed one in addition to three-stringed one has been handed down to subsequent generations through the Fujiue school that was started by Kengyo FUJIUE in Edo during the middle of the Edo period.
胡弓の種類については、通常の三弦のもののほかに、江戸時代中期に江戸において藤植検校が藤植流を創始し、四弦の胡弓が伝承されている。