The following is an alphabetical list of heya or training stables in professional sumo. All belong to one of five groups, called ichimon. These groups, led by the stable by which each group is named, are in order of size: Dewanoumi ichimon, Nishonoseki ichimon, Tokitsukaze ichimon, Takasago ichimon and Isegahama ichimon. Occasionally there have been independent stables, but the Japan Sumo Association agreed at a director's meeting in July 2018 that all sumo elders must belong to one of the five ichimon. The founding dates listed below are for the current incarnation of each stable; in most cases this is not the first stable to exist under a given name, however. The number of stables peaked at 54, with the opening of Onoe stable in August 2006. In order to limit the over-proliferation of stables, the Japan Sumo Association introduced new rules the following month that greatly raised the qualifications needed by former wrestlers wishing to branch out (namely, those ranked below yokozuna or ōzeki must have spent at least 60 tournaments in the top makuuchi division or 25 in the titled san'yaku ranks). Discounting the temporary closure of Kise stable from 2010-2012, over six years no new stables established while eleven folded, bringing the number of stables to 43. The streak of closures ended with the opening of former yokozuna Musashimaru's Musashigawa stable in April 2013, hence the opening and closing of stables has stabilized. There are 44 stables, all of which are located in the Greater Tokyo Region, especially in Tokyo's Ryogoku district. The governing body of professional sumo is the Japan Sumo Association. Six tournaments are held every year: three in Tokyo (January, May and September) and one each in Osaka (March), Nagoya (July) and Fukuoka (November). Each tournament lasts 15 days during which wrestlers compete in one bout per day. All sumo wrestlers are classified in a ranking hierarchy (banzuke), which is updated after each tournament based on the wrestlers' performance. Wrestlers with more wins than losses go up while those with negative records are demoted. The top division is Makuuchi and the second division is Juryo. At the pinnacle of sumo hierarchy is yokozuna.

Pronunciation note

Due to a Japanese speech phenomenon known as rendaku, when the word for stable, heya, comes second in a compound word, the "h" in heya changes to "b" to become beya. A sumo stable is pronounced in Japanese as "sumo-beya" and Arashio stable, as an example, is pronounced "Arashio-beya".

Active stables

There are 46 stables as of May 2024. ! Name ! Ichimon ! Year opened !class="unsortable"|Notable active wrestlers !class="unsortable"|Notable past wrestlers !class="unsortable"|Other notable information Tokitenkū, Aogiyama, Toyonoshima||founded by Futabayama, head is former Tosayutaka who took over when previous head (former Tokitsuumi) was expelled for failure to follow COVID-19 protocols

Mergers and closures (1994 to present)

Name changes (2003 to present)