⚠️ RULE ZERO – Zero Tolerance & Common Sense
In all sports, Rule ZERO applies, which states:
➤ "If you are not sure whether something is allowed, then it is probably NOT allowed."
All rules are based on common sense, the spirit of the sport, and the safety of all participants.
Any deliberate misinterpretation, violation of the meaning of the rules, or attempt to exploit gray areas for unfair advantage will not be tolerated and may lead to team disqualification from the competition.
1. General Aspects
1.1. Definition of the Sumo Match
A. A match is fought between two teams/two robots, each team having one or more members. Only two team members from each team may approach the dohyo. The operator and the assistant will enter the game area, the other team members must watch from the audience. Recording the match is allowed and can be done by the operator, assistant or any other team member. However, only operators and assistants are permitted to be in the game area, no other team members are allowed.
B. In accordance with the game rules (hereafter referred to as "these rules") each team competes on a Dohyo (sumo ring) with a robot that they have constructed themselves to the specifications in Section 2. The match starts at the referee's command and continues until a contestant earns two Yuhkoh points. The referee determines the winner of the match. After the match the operator and the assistant will go to the assigned room and wait there for the next game.
2. General Requirements
2.1. General Robot Specifications
A. Any robot design is allowed, if not subject to the limitations of section 2.2.
B. A robot must fit within a square with the side length of 2.5 cm (25 mm).
C. Maximum height of the robot is 2.5 cm (25 mm).
D. The total mass of a robot at the start of a match must be under 25g.
E. A robot may expand in size after a match begins, but must not physically separate into pieces and must remain a single centralized robot. Robots violating these restrictions shall lose the match. Screws, screw nuts, washers and other robot parts with a total mass of less than 5g falling off from a robot's body, shall not cause the loss of match.
F. All robots must be autonomous. Any control mechanisms can be employed, as long as all components are contained within the robot and the mechanism does not interact with an external control system (human, machine or otherwise).
G. The robots must have displayed a number, offered by the organizers, on the casing of the robot in a visible place for the referee. The number is used to identify the robot by the referee and can be found in the Team's Folder (details in appendix 1).
2.2. Robot Limitations/Restrictions
A. For safety reasons the robot must be equipped with an IR start/stop sensor to be operated by the referee.
B. The robot builder is responsible for adding such a start/stop sensor on the robot. The technical specifications for the IR receiver are given in the appendix 2.
C. Participants can either implement their own hardware or use a prebuilt module sold by our partner shop.
D. It is mandatory for the IR start/stop module to function properly; this means the robot must start and stop when the referee gives the signal using the official remote. The responsibility is entirely of the team. If the module is not on the robot or is not working the team will not be able to compete.
E. During the homologation and in the matches the module must function properly.
F. If a start/stop module issue occurs during a round and the robot fails to stop when the referee sends the signal the round will be lost.
It is recommended and allowed to be replaced, supervised by the referee, (after the round is over). After the sensor was replaced the match will resume if there are still rounds to play.
G. Jamming devices, such as IR LEDs intended to saturate the opponents IR sensors, are not allowed.
H. Parts that could break or damage the dohyo are not allowed. Do not use parts that are intended to damage the opponent’s robot or its operator. Normal pushes and bangs are not considered intent to damage.
I. Devices that can store liquid, powder, gas or other substances for throwing at the opponent are not allowed.
J. Any flaming devices are not allowed.
K. Devices that throw things at your opponent are not allowed.
L. Sticky substances to improve traction are not allowed. Tires and other components of the robot in contact with the dohyo, must not be able to pick up and hold a standard A4 paper (80 g/m2) for more than two seconds.
M. Devices to increase down force are not permitted (e.g. EDF, suction pump etc.).
N. The robot blade or extension can’t be white.
3. Requirements for the Dohyo (Sumo Ring)
3.1. Dohyo Interior
A. The dohyo interior is defined as the playing surface surrounded by and including the border line.
B. Anywhere outside this area is called the dohyo exterior.
3.2. Dohyo Specifications
A. The dohyo shall be circular made from wood with a thickness of 1.25 cm, painted in black with a diameter of 19.25 cm (192.5 mm).
B. The border line is marked as a white circular ring with a width of 0.625 cm (6.25 mm).
C. The Dohyo will be placed on a wooden surface, height 70 - 100 cm (700 - 1000 mm)
D. For all given dohyo dimensions a tolerance of 5% applies.
E. Starting Lines (Shikiri-Sen) 2.5x1 cm (25 x 10 mm)
3.3. Dohyo Exterior
A. There should be a space appropriate for the given class outside the outer edge of the dohyo. This space can be of any color and can be of any material or shape as long as the basic concepts of these rules are not violated.
B. This area, with the dohyo in the middle, is to be called the "dohyo area".
3.4. How to Carry Sumo Matches
A. One match shall consist of 3 rounds, within a total time of 3 minutes, unless extended by the referees.
B. The team who wins two rounds or receives two "Yohkoh" points first, within the time limit, shall win the match. A team receives a "Yohkoh" point when they win a round. If the time limit is reached before one team can get two "Yohkoh" points, and one of the teams has received one "Yohkoh" point, the team with one "Yohkoh" point shall win.
C. 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 "Yohkoh" point shall win. Alternatively, the winner/loser of the match may be decided by referees, by means of lots, or by a rematch.
D. If the robots get stuck, the rules from the point 6.1 will be applied.
E. If one of the two robots won’t start, a restart will be done. If at this restart the same robot won’t start, the match will be won by the robot that moves.
3.5. Course of the Competition
3.5.1. Competition system
The competition will take place in a groups – quarters – semifinals - finals system to allow as many rounds of play as possible for each robot.
Groups
A. The robots will be divided into groups according to the number of participants.
B. The order of the robots in the groups will be made randomly. It will be made after the official opening of the competition and the check-in are over.
C. The groups will be available on the website, for each category and for all the participants.
D. If the number of the participants will not be enough for the groups, the competition will be played from the beginning using the pyramidal system. The position in the pyramid will be random.
E. Each team/robot plays matches with all the other teams/robots in the group („each with each” system).
F. Points are awarded for victory (1 point) and for defeat (0 points). Points are counted in the scoring system for each robot.
G. Each match is played on the best out of the 3 rounds system and will be supervised by 3 referees (a principal one and two assistants).
H. The decisions of the referees must be unanimous and are final. Questioning these decisions leads to disqualification.
I. The ranking of the group is done according to the accumulated points.
J. If two or more teams have the same number of points, it is used tiebreaker criteria such as:
a. difference in points/scores (goal difference)
b. the result of the direct match between the teams
c. other established criteria (e.g.: robot’s willingness to fight, robot’s construction and programming, team behavior etc.).
K. If two robots of the same team play one against the other, they must play the match, without demanding that one of them advance without play or to demand to arrange the matches or the opponents.
L. The ones that pass the groups will play quarters. The top 2 (or more) teams from each group advance.
M. After the group stage is done no objection and changes can be made.
Quarters
A. Qualified teams/robots are divided into pairs (e.g.: 4 groups; 1st grA vs 2nd grD; 2nd grA vs 1st grD; 1st grB vs 2nd grC; 2nd grB vs 1st grC - this system is used even if there are more groups; for any number of groups the algorithm is made starting from group A paired with the last, group B with the penultimate and so on).
B. The quarters (pyramid system) will be available on the website after all the groups are done.
C. Eliminations matches are played – who loses leaves the competition.
D. Each match is played on the best out of the 3 rounds system and will be supervised by 3 referees (a principal one and two assistants).
E. The decisions of the referees must be unanimous and are final. Questioning these decisions leads to disqualification.
F. If two robots of the same team advance to quarters and play one against the other, they must play the match, without demanding that one of them advance without play or to demand to arrange the matches or the opponents.
G. The winning teams/robots advance to semifinals.
Semifinals and Finals
A. The semifinals and finals (pyramid system) will be available on the website.
B. Qualified teams/robots are divided into pairs formed from the last 4 winners.
C. The 2 winning teams/robots from the semifinals face off for the title. The losing teams/robots play a match for 3rd place.
D. Matches are played in the elimination system.
E. Points are awarded for victory (1 point) and for defeat (0 points). Points are counted in the scoring system for each robot.
F. Each match is played on the best out of the 3 rounds system and will be supervised by 3 referees (a principal one and two assistants).
G. The decisions of the refs must be unanimous and are final. Questioning these decisions leads to disqualification.
H. If two robots of the same team advance to the semifinals and finals and play one against the other, they must play the match without demanding that one of them advance without play or to demand to arrange the matches or the opponents.
I. The winning team/robot of the final is declared champion.
3.5.2. Teams and robots
A. Until the homologation, all the teams will stay in the room reserved for them (the room will be marked in the area map). The teams can leave the room only when they are called to the competition area. Each team will be called by a competition official/competition volunteer, when they need to go to the waiting area which is near the competition area.
B. The homologation is made every time for the robots which will follow at start. They will remain in the competition area, in the waiting area. The teams will leave this area only if the referee agrees.
C. After a match is over, the teams must return to the room reserved for them.
D. Each team has the responsibility to follow the starting grid (schedule), displayed on the website. PLEASE DON’T BE LATE, WE WILL NOT WAIT!!!
If you are called to play and you don't come in 5 minutes the robot will lose the match!!!
E. Each team will have one operator and optional, one assistant. Only the operator and the assistant are allowed in the waiting area and in the game area.
F. The rest of the team will remain in the room or will follow the game from the audience.
G. One person can be an operator for a maximum of 2 robots. Operator can’t be changed and is mandatory to be the person who is assigned in the registration system.
H. A picture will be taken at the homologation stage to the robot with the display number visible and also with the badge and operator face.
3.5.3. Matches
A. During the whole contest when playing a match, no breaks are allowed between rounds.
B. Between the matches, the changes, repairs and reprogramming are allowed.
C. Each match is played on the best out of the 3 rounds system and will be supervised by 3 referees (a principal one and two assistants).
D. During a match there will be a short break max. 1 minute between the rounds for cleaning the robot and wheels, configuring the robot and the fight must resume.
E. The robot configuration must be done before placing the robot in the dohyo.
F. Once placed in the dohyo the robot can't be touched.
G. The operator has 5 seconds, starting from the referee's signal, to activate the robot (if it is needed) using a remote control from a safe distance to the dohyo. After that the operator must put the remote down.
H. During each round after the robots are placed on the dohyo, the operator and assistant must not use or have in their hands remotes or other custom made devices that can control the robots. The phone can be used only to record the match. If the phone is not in the camera mode the team will lose the round.
I. The players can't touch or remove the robots from the dohyo after the fight is over until the referee gives them the sign. If the players touch or remove the robot before the referee gives the sign, no objections can be raised.
3.6. Homologation
A. Each team will have to pass the homologation stage, in order to participate with their robots in the competition.
B. The stages of the homologation process are at the beginning of the group and before every match.
3.6.1. At the beginning of the group
A. The presence of the number on the robot will be verified, and it must be clearly visible to the referees. The number can be placed anywhere on the robot's casing and must remain attached throughout the entire competition. However, it is not required for the number to be visible during the match on the dohyo.
B. A photo will be taken to every robot in which the number will be visible.
A photo will be taken to the robot with the display number visible and also with the badge and operator face.
C. Checking the robot dimensions by placing a 2.6cm x 2.6cm (26mm x 26mm) box/frame, bottomless, over the robot.
D. Checking the height of the robot that must be under 2.6 cm (26mm)
E. Weighing the robot on a digital scale. The maximum value must be 26g.
F. Checking the operation of the IR sensor to start and stop the robot on the dohyo. The IR sensor must function properly for both start and stop.
3.6.2. Before every match
A. It will be checked if the number exists on the casing of the robot.
B. Checking the robot dimensions by placing a 2.6cm x 2.6cm (26mm x 26mm) box/frame, bottomless, over the robot.
C. Checking the height of the robot that must be under 2.6 cm (26mm)
D. Weighing the robot on a digital scale. The maximum value must be 26g.
E. Checking the operation of the IR sensor to start and stop the robot. The IR sensor must function properly for both start and stop.
F. After homologation the first group will remain in the waiting area, near the game area. The rest of the teams will return to the room assigned for them.
G. It will be checked to confirm that the operator has not been changed.
4.Start, Stop, Resume, End a Match
4.1. Robot Placing
A. Upon the referee's instructions, the two teams approach the dohyo to place their robots on the dohyo. The operators will place the robots at the same time on the dohyo. The referee will give the signal. After placing, the robots may not be moved anymore.
B. Any part of the robots must be placed behind the Shikiri-Sen (staring lines). The robot shall not go over the starting line toward the opponent.
C. The robot should be placed on and within the extended lines vertically from the both edges of Shikiri-Sen (starting line).
D. The referee will check if the robots are placed ok. If the placement is not correct, the robot positioning will be made again.
4.2. Start
A. In Nano sumo the referee starts every round by sending a start signal with an IR transmitter. As soon as the robots receive the signal the round will start immediately, without any delay.
B. The technical specifications for the IR receiver are given in the appendix 2. Contestants can either implement their own hardware or use a prebuilt module sold by our partner shop.
C. The start will be made after the operator and the assistant will be in the safe area.
D. If the operator and/or the assistant will leave the safe area without referee approval the team can lose a point or can be disqualified.
4.3. Stop, Resume
A. The match stops and resumes when a referee announces so.
B. The referee announces the moment when the robots can be placed on the dohyo, the moment when the operator and/or the assistant to retreat in the safe area and the moment when they can take the robots from the dohyo.
4.4. End
A. The match ends when the referee announces so. The two teams retrieve the robots from the dohyo area after the referee announces it.
B. After the robots are retrieved the decision is final and no objections shall be declared.
5. Time of Match
5.1. Duration
A. One match will be fought for a total of 3 minutes, starting and ending upon the referee's command, after the operator and assistant will retreat to the safe area.
5.2. Extension
A. An extended match, if called for by the referee, shall last for a maximum of 3 minutes.
6. Scoring
6.1. One “Yohkoh” point shall be given when:
A. A team legally forces the body of the opposing robot to touch the space outside the dohyo.
B. The opposing robot has touched the space outside the dohyo on its own.
C. After making contact, Robot A caused Robot B to be completely thrown out of the dohyo. The point is awarded to Robot A, even if it was the first to touch the area outside the dohyo.
D. The opposing robot gets damaged without being able to continue and the team’s representative announces it.
E. Both robots exit the dohyo simultaneously, the robot that is pushed out is considered the loser, even if the pushing robot is the first to touch the area outside the dohyo.
F. Any part that has more than 5g becomes detached from the robot but remains in the dohyo, there will be no penalties from the referees. However, if the part is thrown outside the dohyo, the robot that owns the part loses the round.
G. A robot has 1 or 2 extended blades and one of them touches the outside of the dohyo.
6.2 When referees' decision is called for to decide the winner, the following points will be taken into considerations:
a. Technical merits in movement and operation of a robot
b. Penalty points during the match
c. Attitude of the players during the match
6.3. The match shall be stopped and a rematch started under the following conditions:
A. If one of the two robots doesn’t start there will be one restart.
If at restart the same robot doesn’t start, the point will be won by the robot that moves.
B. The robots are entangled or orbiting each other with no perceivable progress for 10 seconds there will be one restart.
If at restart the situation is repeating, the winner will be the robot that moves more and shows the willingness to fight.
C. If one fast robot gets stuck in a slow robot for more than 5 seconds, there will be one restart.
If the progress is none or the robots move very slow, after 5 seconds the referee stops the match. The teams can't make any objections.
If at restart the situation is repeating, the robot that moves faster and attacks will be the winner of the round.
D. If two fast robots get stuck for more than 5 seconds, there will be one restart.
If the progress is none or the robots move very slow, after 5 seconds the referee stops the match. The teams can't make any objections.
If at restart the situation is repeating, the robot that moves faster and attacks more will be the winner of the round.
E. If both robots are with the wheels on the dohyo and exit the dohyo at the same time and it is not clear which robot touched first outside the dohyo, a rematch will be made and the recordings can be ignored.
F. If one robot has 1 point and in the next round there is no winner, only 2 rematches are allowed. If in the 2 rematches allowed no one wins, the robot that has 1 point will be the winner of the match.
G. Both robots move, without making progress, or stop (at the exact same time) and stay stopped for 5 seconds without touching each other. However, if one robot stops its movement first, after 5 seconds it will be declared as not having the will to fight. In this case the opponent shall receive a “Yohkoh” 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 referee can extend the time limit up to 30 seconds.
H. Important:
In the case the winner can't be declared in any of the above situations, there will be applied a special rule:
A bottle will be placed in the center of the Dohyo and the first robot that touches it with the robot case or blade is declared the winner. It's not considered a valid touch with the flag or other robot extension. The robots will be placed touching the white line
6.4. Repairs, modifications, unpredicted interruptions
A. From the moment a robot passes the homologation (and it is in the waiting area) until the match ends (all rounds are played), no changes can be made to the robot and no breaks are allowed for any of the conditions below:
a. NO repairs are allowed during a match
b. NO battery change or charge is allowed during a match
c. NO blade change is allowed during a match
d. NO reprogramming is allowed during a match (the tactics selection before the fight is not considered programming)
e. if the robot blade is detached from the robot during a round it's not allowed to put it back. The robot must continue fighting without the blade until the match is over
B. The robot must start and finish the match (all rounds played) without any modification (except the tactics selection for the robot) and can not leave the competition area for any reason.
C. During a match there will be a short break max 1 minute between the rounds for cleaning the robot and wheels, configure the robot and the fight must resume.
D. Battery change/charge, repairs or the replacement of defective parts, blades can be made after the match is over until the next match.
E. If a robot gets broken during a match and can't continue, the match is won by the opponent robot. No repair is allowed.
7. Violations
7.1. Violations
A. Players performing any of the deeds described in Sections 2.2, 7.2, 7.3 or 7.4 shall be declared in violation of these rules and it is punishable with a warning.
(If a team has 2 warnings, a ”Yohkoh” point will be given to the opposite team or the team can be disqualified depending on the gravity of the action that they did).
7.2. Participant misbehavior
A. A player who utters insulting words to the opponent or to the referees 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.
B. Yelling at the referees and the opponents is not allowed.
C. Threatening gestures towards referees and opponents are not tolerated.
D. Repeated aggressiveness in language and in behavior of the participants can lead to the elimination of the team from the competition and result in the call of the security guards.
E. Gestures, simbols or offending words written on the outside case of the robot are considered regulations violations.
7.3. Protective gear and the safe area
It is considered serious misconduct in regulation:
A. The operator and/or the assistant doesn’t retreat to the safe area or they don’t comply with the indications of the referee.
B. If the start/stop module doesn’t work or is missing, the robot will not be allowed to compete.
7.4. Minor Violations
7.4.1. A minor violation is punishable with a warning and is declared when:
A. The competitor enters the dohyo during the match, unless the referee stops the match after the grant of a " Yohkoh " point and the contestant goes to pick up the robot. To enter into the dohyo means:
a. a part of the player's body is in the dohyo.
b. a player puts any mechanical kits into the dohyo to support his/her body.
B. Performs the following deeds:
a. touches the robot after it is placed in the dohyo.
b. demand to stop the match without appropriate reasons.
c. take more than 60 seconds before resuming the match, unless the referee announces a time extension.
d. take action of any kind which is contrary to the spirit of fair-play of the game.
e. the operator and/or the assistant will leave the waiting area without announcing the official of the competition or the referee regarding the reason for leaving.
7.5. Major Violations
7.5.1 A major violation is punishable with a 2 ”Yohkoh” points awarded to the adversary when:
A. A robot scratches the paint of the dohyo on a distance more than 5 cm wide by 1 mm on its own.
It is not considered a scratch if it happens during the fight when the robots are engaged.
B. The robot starts moving after being placed on the dohyo, without receiving a start signal from the referee's remote.
C. The robot catches fire. The robot will be disqualified.
8. Penalties
8.1. Penalties
A. Players who violate these rules by performing the deeds described in Sections 2.2, 7.2, 7.3 and 7.5 shall lose the match. The referee shall give two “Yuhkoh” points to the opponent and order the violator to clear out. The violator is not honored with any rights.
B. Each occasion of the violations described in Sections 7.4 shall be accumulated. Two of these violations shall give one ”Yohkoh” point to the opponent.
C. The violations described in Article 7.4 shall be accumulated throughout one match.
9. Declaring Objections
9.1. Declaring Objections
A. No objections shall be declared against the referees' decisions.
B. The operator of a team can present objections to the referee, before the match is over, if there are any doubts in the exercising of these rules.
10. Flexibility of Rules
A. As long as the concept and fundamentals of the rules are observed, these rules shall be flexible enough to encompass the changes in the number of players and of the contents of matches.
B. Modifications or abolition of the rules can be made by the local event organizers as long as they are published prior to the event and are consistently maintained throughout the event.
11. Liability
A. Participating teams are always responsible for their own safety and for the safety of their robots and are liable for any accidents caused by their team members or their robots.
B. The organization and the organizing team members will never be held responsible nor liable for any incidents and / or accidents caused by participating teams or their equipment.
C. The organization and the organizing team members do not produce the IR start/stop sensor.
D. The organization and the organizing team members do not handle the implementation of the code for it and do not provide code for the start/stop sensor.
E. The organization and the organizing team members do not provide any warranty for the IR start/stop sensor.
APPENDIX
📑 Remote start and kill switch
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