The guzheng or gu zheng is a Chinese plucked zither. It has 18 or more strings and movable bridges, and the modern guzheng usually has 21 strings and bridges. The picks (called "DaiMao") used by performers to play guzheng are often made out of the shells of hawksbill turtles.
The guzheng is the ancestor of several 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 with no moveable bridges).
The early types of guzheng emerged during the Warring States period (475 to 221 BCE). It was largely influenced by the se. It became prominent during the Qin period (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 zheng 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 metal-nylon which increased the instrument's capabilities, volume and timbre.
There are many techniques used in the playing of the guzheng, including basic plucking actions (right or both hands) at the right portion and pressing actions at the left portion (by the left hand to produce pitch ornamentations and vibrato) as well as tremolo (right hand). These techniques of playing the guzheng can create sounds that can evoke the sense of a cascading waterfall, thunder, horses' hooves, and even the scenic countryside. Plucking is done mainly by the right hand with four plectra (picks) attached to the fingers. Advanced players may use picks attached to the fingers of both hands. In more traditional performances however, plectra are used solely on the right hand, reflecting its use for melodic purposes and its relative importance in comparison to the left hand which is used solely for purposes of ornamentation. Ancient picks were made of ivory and later also from tortoise shell. Ornamentation includes a tremolo involving the right thumb and index finger rapidly and repeatedly plucking the same note. Another commonly used ornamentation is a wide vibrato, achieved by repeatedly pressing with the left hand on the left side of the bridge. This technique is used liberally in Chinese music, as well as in Korean gayageum music.
The guzheng's pentatonic scale is tuned to Do, Re, Mi, So, and La, but Fa and Ti can also be produced by pressing the strings to the left of the bridges. Well known pieces for the instrument include Yu Zhou Chang Wan (Songs of fishing boats at dusk), Gao Shan Liu Shui (High mountains flowing water), Mei Hua San Nong (Three variations of the Plum Blossom theme) and Han Gong Qiu Yue (Autumn Moon Over the Han Palace).
Two broad playing styles (schools) can be identified as Northern and Southern, although many traditional regional styles still exist. The Northern styles is associated with Henan and Shandon while the Southern style is with the Chaozhou and Hakka regions of eastern Guangdong. Both Gao Shan Liu Shui (High mountains flowing water) and Han Gong Qiu Yue (Han palace autumn moon) are from the Shandong school, while Han ya xi shui (Winter Crows Playing in the Water) and Chu shui lian (Lotus Blossoms Emerging from the Water) are major pieces of the Chaozhou and Hakka repertories respectively.