The zhu is an idiophonic percussion instrument that was used in yayue, the ritual music of ancient China's Zhou dynasty.

This contrasted with the tiger-shaped yu, played by striking the top of its head and crossing the ridges along its back, used to mark the end of the music.

Both instruments appear in Zhou-era annals and the Classic of History[1] but are now rarely used, with surviving examples usually simply displayed in museums and Confucian temples.

The Classic of Music that instructed creation and use of the yayue instruments is almost entirely lost, and aspects of modern construction and performance are guesswork or replacement.

Unlike many Chinese reconstructions of the zhu, which are typically open at the top, the chuk is frequently covered and the performer strikes the bottom of the instrument through a hole for that purpose.