Yokozuna Terunofuji is expected by many to retire in the next ~year. Upon his retirement, how many tournaments will happen with NO Yokozuna listed on the banzuke?

If Terunofuji announces his retirement before a tournament begins, but his name is on the banzuke, the count will start with the subsequent tournament. If he announces his retirement during/after a tournament and his name is not on the following banzuke, that tournament will begin the count.

If the first tournament without his name features another Yokozuna, this resolves 0.

If there is one tournament with no Yokozuna at all, and then there is a new Yokozuna on the following tournament, this resolves 1.

I set the max to 20. If there are more than 20 tournaments with no Yokozuna, we'll resolve to the highest possible figure.

If a banzuke is drawn up for a tournament but no matches in the tournament ever take place for some reason, that tournament will still count for the purposes of this market. If grand sumo tournaments stop happening forever and Terunofuji is the last Yokozuna of all time, this will resolve to the number of tournaments that did take place without him.