The following is an alphabetical list of heya or training stables in professional sumo.
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.
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).
Six tournaments are held every year: three in Tokyo (January, May and September) and one each in Osaka (March), Nagoya (July) and Fukuoka (November).
Wrestlers with more wins than losses go up while those with negative records are demoted.