It's common knowledge that the written banzuke (ranking sheet) contains the name of every single wrestler in professional sumo, from the yokozuna at the top right on down to those at the very bottom of the lowest (jonokuchi) division.

The only problem with that is there are a few rikishi who aren't on the banzuke.

Known as banzuke-gai (literally "outside the banzuke"), they are wrestlers who have failed to show up for any of their seven regularly scheduled bouts in jonokuchi and as a result have been dropped from the rankings completely.

There is no limit on how long a rikishi can remain banzuke-gai. There are currently seven wrestlers in sumo with the designation. One of those men Kotonawa, has been banzuke-gai for three years after just a single year of activity in the sport.

It's often the case that after a young wrestler runs away and has been gone from sumo for a year or more, the stablemasters still haven't handed in their retirement papers.

The main reason for that is sumo is a one-chance sport. Once you are officially retired you may never rejoin.

Stablemasters give a lot of leeway as a result, not wanting to end a potential career in case the wrestler in question changes his mind after some reflection and personal growth.

Once a runaway returns or an injured rikishi has healed and wishes to fight again, he isn't automatically added to the banzuke.

Instead he must go through a mini round-robin competition known as maezumo (pre-sumo) with whatever newcomers have joined sumo prior to that tournament.

As well as being no limit on how long a wrestler can be banzuke-gai there is no rule preventing someone falling into that status on numerous occasions.