Huqin (胡琴; pinyin: húqín) is a family of bowed string instruments, more specifically, a spike fiddle popularly used in Chinese music. The instruments consist of a round, hexagonal, or octagonal sound box at the bottom with a neck attached that protrudes upwards. They also have two strings (except the sihu, which has four strings tuned in pairs) and their soundboxes are typically covered with either snakeskin (most often python) or thin wood. Huqin instruments have either two (or, more rarely, four) tuning pegs, one peg for each string. The pegs are attached horizontally through holes drilled in the instrument's neck. Most huqin have the bow hair pass in between the strings.
The most common huqin are the erhu, which are tuned to a middle range; zhonghu, which is tuned to a lower register, and gaohu, which is tuned to the highest pitch. Over thirty types of huqin instruments have been documented.
Huqin instruments are believed to descend from an instrument called the xiqin (奚琴), originally played by the Xi, a nomadic people of Central Asia.
In the 20th century, large bass huqin such as the dihu, gehu, and diyingehu were developed for use in modern Chinese orchestras. Of these, the gehu and diyingehu would be analogous to occidental double basses, and were designed to have a timbre that would blend in with the sound of traditional huqin. These instruments generally have four strings and fingerboards, and are played in a similar manner to cellos and double basses, and are very different from the traditional huqin.