The zheng (or cheng) is a Chinese plucked string instrument.
Its earliest popularity was during the Warring States period (476-221
B.C.). It is Made of wood with wound silk strings, with the dimensions
180 cm long by 20 cm wide. Southern Chinese zheng use metal strings
(steel or brass) rather than silk. There are different kinds of zheng
with different numbers of strings from 12 to 16. Modern zheng's have
various numbers of strings: 18, 19, 21, 23 and 25, with 21 strings being
the most common.
The Japanese koto and the Korean
kayagum are closely related instruments
to the zheng. The koto was introduced into Japanese court music
from China in the 7-8th centuries.
Here is a picture of a performer using the zheng: