Kyū (Japanese: 級, [kʲɯː]) is a Japanese term used in modern martial arts as well as in tea ceremony, flower arranging, Go, shogi, academic tests and other similar activities to designate various grades, levels or degrees of proficiency or experience.

[2] In modern Japanese martial arts, kyū-level practitioners hold the ranks below dan or black belt.

[3] Kyū-level practitioners are often called mudansha (無段者), "ones without rank", and are considered as initiates rather than students.

The wearing of coloured belts is often associated with kyū ranks, particularly in modern martial arts such as karate and judo (where the practice originated).

Historically, students of martial arts would only have one belt or obi, which they would hand-dye when the next ranking was achieved.

[citation needed] [5] The system of using different colored belts to mark rank is not universally accepted in the martial arts.