How a bout is won, and how a tournament works
Sumo has one of the shortest rulebooks in sport. Two wrestlers start from a crouch behind their lines; the bout is over the moment one of them steps out of the ring or touches the ground with anything other than the soles of his feet. Most bouts last a few seconds.
A wrestler loses if any of these happen:
There are no weight classes and no rounds. A 100 kg wrestler can be drawn against one twice his size.
Every bout is recorded with the technique that decided it — the kimarite. There are 82 recognised techniques plus five non-technique results, and the judges announce which one applied. This is why sumo has unusually rich data for such a simple sport: every one of the 747,775 bouts on this site carries the way it was won.
Six tournaments (basho) are held each year, in January, March, May, July, September and November. Each runs fifteen days, Sunday to Sunday. Wrestlers in the top two divisions fight once a day, fifteen bouts in all; those in the lower divisions fight seven times over the fifteen days.
There are no knockouts and no brackets. The wrestler with the most wins at the end takes the championship (yusho); if two or more are level, they meet in a play-off on the final day.
Wrestlers from the same stable do not normally meet, except in a play-off.
Eight wins from fifteen is a winning record — kachikoshi — and moves a wrestler up the ranking. Seven or fewer is makekoshi, and moves him down. This single threshold drives the whole sport: on the last day, a wrestler sitting on seven wins is fighting for his rank, his salary and, further down the ranks, his living.
Besides the championship, three special prizes are awarded in the top division: shukun-sho for an outstanding performance, kanto-sho for fighting spirit, and gino-sho for technique. A rank-and-file wrestler who beats a grand champion is also credited with a kinboshi, a “gold star”, which is worth a permanent addition to his pay.
The dohyo is a clay platform about 34 cm high with a ring of rice-straw bales 4.55 m across. It is rebuilt for every tournament. The roof suspended above it is modelled on a Shinto shrine, and the ritual around the bout — the salt thrown to purify the ring, the stamping, the ladle of water — comes from the same source. The salt is not decoration: several hundred kilograms of it are thrown over the course of a tournament.