The number of stables in sumo continuously ebbs and flows.
Keeping track of, and deciphering the motives behind, the endless elder stock-related openings, closings and mergers, is akin to following the shifting allegiances in the TV series "Game of Thrones."
Some heya of course, like Dewanoumi and Takasago, have been in operation uninterrupted since the 1800s, but many others are either newer incarnations of previously shuttered stables, or recent additions to the list.