Mr. Yu is a single-reed gas-sounding instrument of the Jingpo and De'ang peoples. In Jingpo language, "Bi" is a general term for air-sounding musical instruments, and "general" means double, which means a pair of air-sounding musical instruments with parallel pipes. Folks have the same style but different specifications.

When playing the kiji, there are two mouthpieces in the mouth, which can be played horizontally or vertically. The playing method and technique are the same as Ruizuo.

The main sound range is g-a1, and the auxiliary pipe is pronounced as a, which is a second-degree relationship with the main tone, and an octave away from the main treble. The sound is rich. Some players have bamboo strips in the supervisor, which makes the pronunciation dull and has a strong nasal sound.

Kunge is often used for solo entertainment and is a favorite wind instrument for the elderly of Jingpo people. The music is mostly folk songs.