The guzheng, or guzheng (pinyin: gǔzhēng) or zheng (筝) (gu means "ancient"), is a traditional Chinese musical instrument that has captivated listeners for over two millennia. It belongs to the zither family of stringed instruments, and its unique sound and playing techniques make it a cherished part of Chinese music.

Description:
The modern-day guzheng is a plucked, half-tube zither with movable bridges and 21 strings, although it can have anywhere from 15 to 25 strings (a customized version exists with more than 34 strings). The strings were formerly made of twisted silk, but by the 20th century, most players used metal strings (generally steel for the high strings and copper-wound steel for the bass strings). Since the mid-20th century, most performers use steel strings flatwound with nylon. The guzheng has a large resonant cavity made of wutong wood (Paulownia tomentosa), and other components may be made of other woods, usually for structural and decorative purposes.

History:
The guzheng has existed since the Warring States Period (BC 403-221) and became especially popular during the Qin Dynasty (AD 1636-1911). The ancient guzheng had 12 strings, which gradually evolved into its current form. Until 1961, the common guzheng had 18 strings. In 1961, Xu Zhengao together with Wang Xunzhi introduced the first 21-string guzheng after two years of research and development. They also invented the "S-shaped" left string rest, which was quickly adopted by all guzheng makers and is still used today, whether in the shape of the letter "S," "C," etc. The 21-string zheng is the most commonly used, but some traditional musicians still use the 16-string, especially along the southeastern coastal provinces of China and in Taiwan.

Playing Styles and Techniques:
There are many techniques used in playing 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 can create sounds that evoke the sense of a cascading waterfall, thunder, 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. Ancient picks were made of ivory and later also from tortoiseshell.

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" (Singing at Night on a Fishing Boat), "Gao Shan Liu Shui" (High Mountains Flowing Water), and "Han Gong Qiu Yue" (Han Palace Autumn Moon).

Two broad playing styles (schools) can be identified as Northern and Southern, although many traditional regional styles still exist. The Northern style is associated with Henan and Shandong, 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 repertoires, respectively.

In conclusion, the guzheng is not only a beautiful instrument but also a significant cultural symbol of China, carrying the richness and diversity of traditional Chinese music into the modern era. Its unique sound, intricate playing techniques, and long history make it a timeless treasure that continues to enchant audiences around the world.