Edo beginnings were not the modern system unchanged
The Japan Sumo Association traces a prototype to the Hōreki era, 1751–64: an organizational office developed into elders training disciples at their homes. Domain-sponsored wrestlers also shaped Edo sumo. Match-avoidance relationships then did not simply reproduce today’s rules.
Domain affiliation could take priority in Edo sumo
The association’s historical account describes heya as both an organizational office and an elder’s training household. The teacher–disciple connection principally involved instruction, supervision and status guarantees. Many wrestlers also depended on daimyo patrons, with domain affiliation taking precedence.
Scheduled bouts between stablemates could occur, while wrestlers of the same domain avoided one another. Today’s normal avoidance between stablemates cannot simply be projected back over that combination of patronage and teaching relationships.
Stables within a modern association
The Meiji transition disrupted the support wrestlers had received from daimyo. Keiko Morita’s study describes a later shift towards commercial patrons. The Dai-Nippon Sumo Association became a foundation in 1925, and the Tokyo and Osaka associations merged in 1927. Stables thus operated within a changing national organization, beyond the Edo setting of domain patrons and elders training disciples. The stable remained a training unit within a wider system of tournaments and association administration.
Stablemates normally do not meet in scheduled bouts
Stablemates normally avoid one another in scheduled tournament bouts, with exceptions for championship playoffs. Stables also belong to broader ichimon networks. An ichimon is not a single communal household or the same organizational level as a heya. In July 1989, Kokonoe stablemates Chiyonofuji and Hokutoumi met in a championship playoff.
A network can share practice without becoming one household
Former wrestler Shinzaburō describes ichimon joint practice, bringing wrestlers from different stables to one ring, sometimes with visiting wrestlers from outside the group. Shared practice does not automatically replace their separate stable affiliations.
Succession is a different change. In 2025 the association approved Terunofuji’s succession to the Isegahama elder name and stable; Arashio’s 2020 succession is another named example. The elder name, responsibility for teaching and wrestlers’ affiliations are connected, without making every change of stablemaster a fresh recruitment of all members.
A directory is a snapshot
Arashio offers a concrete example: former komusubi Ōyutaka founded the stable in 2002, and former maegashira Sōkokurai succeeded him in 2020. A change of stablemaster need not mean a newly formed household. Stables can also move, merge or close, so affiliation needs a date and an association record.