Wikipedia
The guzheng , also known as Chinese zither, is a Chinese traditional plucked musical string instrument with over 2500 years of history. It has 16 (or more) strings and movable bridges. The modern guzheng usually has 21 strings with a length of 64 inches. The guzheng has a large resonant cavity made from Wutong wood (Paulownia elongate). Other components often are made from other woods; usually for structural and decorative purposes. Performers playing the guzheng often wear finger picks on right hand or both hands. The picks can be made of different materials such as Ivory, tortoise shell, resin and hard plastic.
The guzheng inspired several other Asian zither instruments, such as the Japanese koto, the Korean gayageum, and the Vietnamese đàn tranh. The guzheng should not be confused with the guqin (another ancient Chinese zither without moveable bridges).
The early types of guzheng emerged during the Warring States period (475 to 221 BCE) where slaughtering cattle, hogs, horses and especially dogs was commonplace. The intestines of these animals made catgut which was used as strings for the guzheng. It was largely influenced by the se. It became prominent during the Qin dynasty(221 to 206 BCE), and by the Tang Dynasty (618 CE to 907 CE), the guzheng was arguably the most commonly played instrument in China. Musicological studies in the late 20th century indicate that early bamboo tube zithers might be one of the prototypes of the guzheng, koto, gayageum, and the đàn tranh.
The modern guzheng is very different from ones made centuries ago, mainly due to natural evolution influenced by local as well as historical environments but also because of the adoption of Western musical styles. Strings were once made from silk but now they are almost always steel string which increased the instrument's capabilities, volume and timbre.