Sumo (JSA) — Official Rules

Sumo is a one-on-one grappling combat sport in which two competitors — designated East (higashi) and West (nishi) — face off on a raised clay ring, the dohyo, wearing only a mawashi (loincloth belt). The competitors make the best possible use of the 4.55 m diameter ring and contest a single decisive bout using their full strength. Each bout produces one winner and one loser — there are no draws and no points accumulated across the bout; the winner is decided the instant the bout ends. Competitions are open to men and women, but no contest between a man and a woman is permitted.

Unless otherwise provided, the winner of a bout is determined by either of the following: (1) the competitor who moves his/her opponent out of the shobu-dawara — the straw bales that form the circle of the dohyo; or (2) the competitor who forces any part of the opponent's body, other than the soles of the feet, to touch the ground before the opponent does the same. Whichever occurs first decides the bout, and the bout ends immediately. The specific technique that produces the result is called a kimarite (officially recognised winning technique).

The gyoji (referee) must in all cases determine the winner at the instant the bout is over. At the moment the winner is decided the gyoji calls "Shobu atta!" ("The contest is decided!") and points to the East or West side. Before the formal announcement (kachi-nanori) the gyoji returns to the basic position, has both competitors stand and bow on the call "Rei!", and then announces "Higashi no kachi" (East's victory) or "Nishi no kachi" (West's victory) while pointing at the winner. Once the kachi-nanori is given, the decision is final and no objection may be raised.

The gyoji signals the tachiai (jump-off) by calling out "Hakkeyoi!" ("Get moving!"). Both competitors' hands must touch down behind the shikiri-sen (the two starting lines). A so-called "tachiai" in which the hands are merely placed on the dohyo for a moment is not permitted. If a competitor jumps off without waiting for the call, the gyoji must call "Matta!" ("Wait!") and start the tachiai again.

The September 2024 revision tightened the tachiai to curb time-wasting and gamesmanship. From the basic position the gyoji steps forward as the competitors meet at center. When they drop into the sonkyo (squat), the gyoji confirms their breathing is synchronised and calls "Kamaete!" ("Take positions!"), then "Ryote o doujini tsuite!" ("Put both hands on the ground simultaneously!"). Upon confirming both wrestlers have placed their hands, the gyoji calls "Hikimasuyo!" ("Get ready!") and completes the tachiai with "Hakkeyoi." A wrestler who places his hands down before the opponent is held back with "Madayo, Madayo" ("Not yet, not yet"), while the other is urged with "Te o tsuite" ("Put your hands down") — so neither side can gain an unfair jump.

If the head judge considers the tachiai to be incomplete, he immediately raises his right hand and stops the bout, and the tachiai is begun again at once; the decision on whether a tachiai was correct rests with the head judge. The gyoji must endeavour to bring both competitors and himself into complete synchronisation at the tachiai. A matta (false start) — jumping before the call, or failing to touch both hands down properly — is corrected by restarting the charge, not by a points penalty; but deliberately failing to jump off to begin the bout is a ground for losing the bout (see Article 6.1).

If a bout goes on for over three minutes without coming to a conclusion, the bout is stopped and a torinaoshi (re-match) is ordered. At a signal given by the timekeeper (the shomen/front judge, per Article 2), the head judge instructs the gyoji to stop the bout. The re-match is then contested afresh. There is no scoring on time and no clock-based winner: the time limit serves only to reset a deadlocked bout. (The default match settings in the scoring engine reflect this with a 300-second bout limit.)

If the gyoji mistakenly calls "Shobu atta!" (declaring the contest decided) while a bout is still in progress, the head judge or any judge lodges an objection, and after deliberation a torinaoshi (re-match) is declared. A torinaoshi may likewise follow a judges' deliberation that cannot otherwise determine the winner. The engine records each torinaoshi and increments the bout's rematch count so the audit trail shows how many times the bout was restarted.

The most common kimarite drive the opponent out of the ring. Yorikiri (force-out) — gripping the opponent's mawashi and walking or carrying them backward over the shobu-dawara — is the single most frequent winning technique. Oshidashi (push-out) forces the opponent out without a belt grip, pushing the body. Tsukidashi (thrust-out) drives the opponent out with a rapid series of open-hand thrusts to the chest or throat area. In each case the bout ends the instant the opponent crosses out of the straw-bale circle, and the gyoji declares the winner.

Other kimarite win by putting the opponent down to the ground first. Uwatenage (overarm throw) swings the opponent down using an overarm grip on the mawashi. Hatakikomi (slap-down) pulls or slaps the charging opponent down to the clay, typically by sidestepping the tachiai. Any of the many recognised techniques (over 80 official kimarite exist) that legally puts a body part other than the soles of the feet to the ground first wins the bout. In the scoring console, techniques outside the common presets are recorded via other_kimarite with the technique name attached.

When the opponent is in the shinitai position — a "dead body", i.e. a falling position in which the competitor has completely lost balance and cannot recover — the winning competitor does not lose even if either of the following then occurs: (1) he/she puts a hand to the ground a moment before the opponent lands (this is kabaite, the "protecting hand"); or (2) he/she steps out of the shobu-dawara a moment in advance of the falling opponent (this is kabaiashi, the "protecting foot"). Because the opponent was already shinitai, the otherwise-losing touch or step-out does not count against the winner.

When a competitor lifts the opponent clear of the ground and carries them forward out of the shobu-dawara, it is not a loss if the carrier's foot goes out first (okuri-ashi); however, if the carrier steps out backward, it is a loss. Likewise, when a bout is won by a throwing technique, the thrower does not lose if the instep of the foot turns over and touches the ground before the opponent lands. These exceptions protect the wrestler executing the winning action from being penalised for an incidental touch that is part of completing the technique.

It is not a loss if the orikomi (front fold) of the mawashi (loincloth belt) touches the ground. Only a body part other than the soles of the feet touching the ground counts as a loss; the cloth of the belt itself contacting the clay is disregarded. This distinguishes the belt — equipment — from the wrestler's body for the purpose of deciding the bout.

The following are kinjite (prohibited moves): (1) punching the opponent with a closed fist; (2) poking the opponent with the fingers; (3) kicking the opponent in the chest or abdomen; (4) taking hold of the opponent's hair; (5) taking hold of the opponent's throat; (6) taking hold of clothing other than the mawashi (underpants, leotard, bandages, support pads) twice or more; (7) taking hold of the maebukuro/maetatemitsu (front vertical part of the mawashi) or sticking fingers in at the side and pulling; (8) bending back one or two of the opponent's fingers; (9) biting; and (10) slapping the opponent's face with an arm outstretched more than a shoulder width. When any kinjite is used, the gyoji must stop the bout immediately.

Using a kinjite causes the offender to lose the bout by hansoku (disqualification) after a judges' deliberation, and the opponent is declared the winner (Article 13(2)). Hansoku is recorded against the offending side in the scoring console; the engine then awards the win to the other side. Unlike a matta or a torinaoshi, hansoku ends the bout with a result and is not replayed. The gyoji must also order a wrestler to release immediately if he grips the tatemawashi/orikomi, grasps non-mawashi clothing for the first time, or applies a gassho clasp (both arms around the opponent with hands clasped) — a first such grip is corrected by the release order rather than by instant hansoku (Article 28).

After deliberation by the judges, a competitor may be judged to have lost in any of the following cases: (1) ruled unable to continue through injury etc.; (2) ruled to have used a kinjite; (3) arbitrarily terminating the bout; (4) ruled to have deliberately failed to jump off to begin the bout; (5) not abiding by the judges' instructions; (6) the maebukuro (front pouch) of the mawashi comes undone and falls away during the bout; or (7) not appearing in the dohyo-damari (ringside waiting area) after being called twice. Each of these results in a loss recorded against that competitor, with the opponent declared the winner.

If the head judge or any judge has an objection or doubt about the gyoji's decision, he raises his right hand immediately and lodges it — this conference is the mono-ii. The objection must clearly point out a kimarite and be stated plainly and concisely. In the event of an objection, the video recorded by equipment installed under the dohyo shall, in principle, be viewed to contribute to the consultation. Once the gyoji has given the kachi-nanori (formal winner announcement), the decision is final and no objection may be raised.

When an objection is raised the whole judging panel immediately moves to the centre of the dohyo and discusses the matter, taking the gyoji's stated reasons into account. A judge may abstain if the deciding move was hidden from his view, and no judge may press his own opinion so strongly as to impede the deliberation. The head judge makes the final judgment and announces a clear, concise explanation; in principle the decision is reached by a majority vote of the judges (excluding the gyoji). The head judge then tries to convince any minority of the validity of the majority decision.

When a judge has confirmed the bout is decided but the gyoji does not call it: (1) if there is a visible mark on the ground (e.g. a fumikoshi stepping-out trace in the janome, the swept-sand circle just outside the shobu-dawara), the judge who saw it raises his right hand to signal the end, the head judge instructs the gyoji to stop, and the result is decided by deliberation; (2) if no visible mark is confirmed, an objection is lodged at the bout's end and the decision is reached through deliberation. The janome's swept sand thus provides physical evidence of a step-out at the ring's edge.

A judging panel consists of a head judge, a gyoji (referee) and four judges — six members in total. The head judge is entirely responsible for determining the result of a bout. The gyoji controls the bout from the moment the competitors mount the dohyo until they step down on completion. The four judges assist the head judge to ensure there are no errors in the decision, and the shomen (front) judge also acts as the timekeeper. The gyoji wears white pants, a white shirt and a black bow tie; the head judge and judges wear suits, white shirts and ties.

The bout is contested on the dohyo, a raised clay ring whose fighting circle — bounded by the shobu-dawara straw bales — is 4.55 m (15 shaku) in diameter. Just inside, two shikiri-sen starting lines mark where the wrestlers set for the tachiai, and the janome (swept-sand ring) lies just outside the bales. Each competitor wears only the mawashi, a heavy silk or cotton loincloth belt wound several times around the waist and between the legs; no metal posts, stones or other hard objects may be worn, and supporters/bandages other than the mawashi are watched closely by the judges for safety.

When a competitor is injured during a bout, the gyoji must stop the bout immediately; the judges consult Medical Committee members and respect their diagnosis in deciding whether the bout can be resumed. A competitor ruled unable to continue loses (Article 13(1)). When a mawashi becomes loose, the gyoji calls "Matte!" to halt the bout temporarily and both wrestlers freeze in their positions (kumite); the gyoji must not stop the bout during offensive moves. After re-tightening the mawashi and confirming with the judges that neither wrestler has shifted, the gyoji places his hands on their backs, calls "Hikimasuyo! Hikimasuyo!" and restarts by lightly tapping their backs and calling "Hakkeyoi!"

IFS individual competition is contested in weight categories. Men: Lightweight under 85 kg, Middleweight 85 kg to under 115 kg (with a Light-Heavyweight band 100 kg to under 115 kg), Heavyweight 115 kg and over, and Openweight (no limit). Women: Lightweight under 65 kg, Middleweight 65 kg to under 73 kg (with a Light-Heavyweight band 73 kg to under 80 kg), Heavyweight 80 kg and over, and Openweight. Competitions are open to both sexes, but no man-versus-woman contest is held.

Junior competition (ages 13–18) uses age-adjusted bands. Junior Men: Lightweight under 80 kg, Middleweight 80 kg to under 100 kg, Heavyweight 100 kg and over, and Openweight. Junior Women: Lightweight under 60 kg, Middleweight 60 kg to under 75 kg, Heavyweight 75 kg and over, and Openweight. As with seniors, weigh-in places each junior in the correct category and no mixed-sex contests are held.

In team competition each side fields wrestlers in fixed order positions — Senpo (lead), Chuken (middle) and Taisho (captain/anchor), with a Substitute available — and the two teams meet bout-for-bout, the team winning more individual bouts taking the tie. At the start and end of a team competition the gyoji stands in the basic position, has all East and West competitors line up and gives the command "Rei!" for a standing bow. Each individual bout within the team tie is decided by the same rules as a singles bout (Articles 8–16), and a deadlocked bout over three minutes is restarted as a torinaoshi.