Sumo Event Rules

Robo Rumble Sumo Rules

Robots per Match:  Two

Length of Match:  3 minutes

Robot Control: Autonomous

Event Summary:  

Robotic Sumo Matches: Two robots compete in a head-to-head match following the basic system of traditional human sumo matches. Robots are allowed no weapons. The sole purpose is a pushing match between the two robots to force the other from the arena.

Requirements for Robots

Size Limits: 

Height = Unlimited 

Width = 30 cm 

Length = 30 cm 

Weight = 2300 g 

- Must not exceed the maximum number of programming blocks, sensors and motors that are available in a single kit (see diagram for details) NXT kit EV3 kit   

- The total mass of a robot at the start of a match must be under the designated weight (2.3kg).

- Robots must be autonomous. Any method of control may be used, as long as it is fully contained within the robot and receives no external signals or directions (human, machine, or otherwise). 

- The robot must have a name or number for registration purposes. Contestants may display this name or number on your robot to allow spectators and officials to identify your robot.

- Materials outside of the Lego NXT and Lego EV3 kits are not permitted.  

Robotic Sumo Rules

Definition of the Match [Definition] A match is fought between two teams, each team having one or more contestants. Only one team member may approach the ring; other team members must watch from the audience. In accordance with the game rules each team competes on the ring with a robot that they have constructed themselves to the specifications in “Robot Requirements”. The match starts at the judge's command and continues until a contestant is wins two matches. The judge determines the winner of the match.

Requirements for the Ring 

(50% bigger than last year)

Material = Laminate or Melamine covered wood 

Height = 3.75 cm 

Diameter = 115.5 cm 

Width = 1.5 cm 

Length = 15cm 

Separation = 15 cm

*inner lines should be dark yellow/brown*

How to Run Matches

1. One match shall consist of 3 rounds, within a total time of 3 minutes, unless extended by the judges.

2. The team who wins two rounds, shall win the match. A team receives a point when they win a round. If the time limit is reached before one team can get two points, and one of the teams has received one point, the team with one point shall win.

3. When the match is not won by either team within the time limit, an extended match may be fought, during which the team who receives the first point shall win. Alternatively, the winner/loser of the match may be decided by judges, by means of lots, or by a rematch.

4. One point shall be given to the winner when the judges' decision was called for or lots were employed.

Start, Stop, Resume, End a Match

[Start] Upon the judge's instructions, the two teams place a robot within their half of the ring on or behind the starting line. (A robot or a part of a robot may not be placed beyond the front edge of the starting line toward the opponent. Note that is not required that a robot be placed directly behind the starting line; it may be offset to the side, as long as it is behind the starting line.) When the judge announces the start of the round, the teams start their robots.

[Stop, Resume] The match stops and resumes when a judge announces so.

[End] The match ends when the judge announces so. The two teams retrieve the robots from the ring area. 

Time of Match

[Time of Match] One Match will be fought for a total of 3 minutes, starting and ending upon the judge's command. 

An extended match, if called for by the judge, shall last for a maximum of 3 minutes.

The following are not included in the time of the match:

1. The time elapsed after the judge announces a match winner and before the match resumes. The standard delay before the match resumes shall be 30 seconds.

2. The time elapsed after a judge announces to stop the match and before the match resumes.

Winning a match 

One point shall be given when:

1. A team legally forces the body of the opposing robot to touch the space outside the ring, which includes the side of the ring itself.

2. A point is also given in the following cases:

The opposing robot has touched the space outside the ring on its own.

Either of the above takes place at the same time that the end of the Match is announced.

3. When a wheeled robot has fallen over on the ring or in similar conditions, the match continues.

4. When judges' decision is called for to decide the winner, the following points will be taken into consideration:

Technical merits in movement and operation of a robot

Penalty points during the match

Attitude of the players during the match

5. The match shall be stopped and a rematch started under the following conditions:

The robots are entangled or orbiting each other with no perceivable progress for five seconds. If it is unclear whether progress is being made or not, the judge can extend the time limit for observable progress for up to 30 seconds.

Both robots move, without making progress, or stop (at the exact same time) and stay stopped for five seconds without touching each other. However, if one robot stops it's movement first, after five seconds it will be declared as not having the will to fight. In this case the opponent shall receive a point, even if the opponent also stops. If both robots are moving and it isn't clear if progress is being made or not, the judge can extend the time limit up to 30 seconds.

If both robots touch the outside of the ring at about the same time, and it can not be determined which touched first, a rematch is called."


[Violations] Players performing any of the deeds described shall be declared in violation of these rules.

[Insults] A player who utters insulting words to the opponent or to the judges or puts voice devices in a robot to utter insulting words or writes insulting words on the body of a robot, or performs any insulting action, is in violation of these rules.

[Minor Violations] A minor violation is declared if a player:

1. Enters into the ring during the match, except when the player does so to take the robot out of the ring upon the judge's announcement of a point or stopping the match. To enter into the ring means:

A part of the player's body is in the ring, or

A player puts any mechanical kits into the ring to support his/her body.

2. Performs the following deeds:

Demand to stop the match without appropriate reasons.

Take more than 30 seconds before resuming the match, unless the judge announces a time extension.

Start operating the robot within five seconds after the chief judge announces the start of the match.

Does or says that which disgraces the fairness of the match."


 [Penalties] Players who violate these rules by including illegal parts or insulting another player shall lose the match. The judge shall give two points to the opponent and order the violator to clear out. The violator is not honored with any rights.

Each occasion of the violations described in shall be accumulated. Two of these violations shall give one point to the opponent.

The violations described in shall be accumulated throughout one match."

Injuries and Accidents during the Match

[Request to Stop the Match] A player can request to stop the game when he/she is injured or his/her robot had an accident and the game cannot continue.

[Unable to Continue the Match] When the game cannot continue due to player's injury or robot's accident, the player who is the cause of such injury or accident loses the match. When it is not clear which team is such a cause, the player who cannot continue the game, or who requests to stop the game, shall be declared the loser.

[Time Required to Handle Injury/Accident] Whether the game should continue in case of injury or accident shall be decided by the judges and the Committee members. The decision process shall take no longer than five minutes.

[Points Given to the Player who Cannot Continue] The winner decided shall gain two points (winning the match). The loser who already gained one point is recorded as such. When the situation takes place during an extended match, the winner shall gain one point."

Declaring Objections

[Declaring Objections] No objections shall be declared against the judges' decisions.

The lead person of a team can present objections to the Committee, before the match is over, if there are any doubts in exercising these rules. If there are no Committee members present, the objection can be presented to the judge before the match is over.

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