Which Japanese organization governs professional sumo?

The Japan Sumo Association governs professional sumo in Japan. It oversees the major tournaments, wrestler rankings, training stables, referees, and other official operations.

The association is commonly abbreviated as NSK, from its Japanese name, Nihon Sumo Kyokai. It is a public-interest incorporated foundation and operates the professional sumo system recognized in Japan.

Its responsibilities include organizing the six annual honbasho, managing the banzuke ranking lists, and supervising the oyakata who run stables. The organization also handles retirement ceremonies, wrestler licensing, and many rules of tournament administration.

The Japan Sumo Association is distinct from local amateur and university sumo bodies. Professional sumo has its own tightly structured stable system and ranking hierarchy, with the association serving as the sport’s central governing institution.