Erhu is a kind of violin (fiddle) with an exception that it has only two strings.
The Erhu instrument belongs to the "huqin" family together with zhonghu, gaohu, sihu, etc.
The term huqin was first mentioned in the Song dynasty (960-1279).
Earlier on, the reference to ji qin first appeared in the Tang dynasty (618-907).
Ji Kang (223-263), a famous literati musician, was attributed as its creator.
Later, the reference to xi qin, named after a northern nomadic tribe Xi, first appeared in Song dynasty (960-1279).
These two instruments were both first described as plucked string instruments, and later as having two strings and being played by pressuring the strings with a strip of bamboo, suggesting that the earliest Chinese bowed instruments were derived from plucked stringed instruments.
These various instruments were perhaps assimilated over a long historical period.
Eventually in the Yuan dynasty (1279-1368), under the Mongolian's rule, both the description of huqin in writing and the portrayal of huqin in painting came to resemble today's erhu.
During Qing dynasty (1644-1911), the erhu instrument underwent a great development at the time of the golden age of the local operas.
The erhu then developed in a different style.
Two famous artists Hua Yanjun (1893-1950) and Liu Tianhua (1895-1932) made an exceptional contribution to the improvement of the erhu, and it was indeed due to the latter that the erhu, an instrument mainly for accompaniment in an opera, becomes a solo instrument.
After the foundation of People's Republic of China (1949), the manufacture of the erhu, the playing techniques, the repertoire as well as the musical education of this instrument have undergone an unpresidented development.
The repertoire has grown rapidly in the genres of solo, with ensemble as well as concerti with symphony orchestra.
Erhu now has become one of the most popular instruments in China.
References:
Stock, Jonathan. 1996. Musical Creativity in Twentieth-Century China: Abing, His Music, and Its Changing Meanings. Rochester, NY: University of Rochester Press.
Liu, Terrence. 2002. "Erhu." In The Garland Encyclopedia of World Music, Vol. 7. East Asia: China, Japan, and Korea, ed. by Robert Provine, Yoshihiko Tokumaru, and J. Lawrence Witzleben, New York: Routledge, 175-8.
Zheng, Su. 2002. "Musical Instruments." In The Garland Encyclopedia of World Music, Vol. 7. East Asia: China, Japan, and Korea, ed. by Robert Provine, Yoshihiko Tokumaru, and J. Lawrence Witzleben, New York: Routledge, 79-83.