noun
dan-kyu ranking system
A hierarchical ranking system using dan (段) and kyu (級) levels, commonly used in martial arts, board games like go and shogi, and other traditional disciplines.
柔道や囲碁では段級制が採用されている。
Judo and go use a dan-kyu ranking system.
級 refers to a specific kyu rank, the lower tier of the system, whereas 段級制 encompasses both dan and kyu levels.
Compound of 段 (dan, 'step' or 'grade'), 級 (kyu, 'class' or 'rank'), and 制 (sei, 'system'). The dan-kyu system originated in Japanese martial arts and board games.