1.Difination

​The SUMO LEGO 1 KG Auto competition is a robotic contest where two teams, each represented by one member, compete by placing their self-built robots on a sumo ring (Dohyo). The match continues until one team accumulates two Yuhkoh points, thereby winning the match

2.Participant Categories

2.1 Each robot team consists of 1 or 2 members (excluding the team mentor)

2.2 Age Categories

  • 2.2.1 Junior All Spike – For participants aged 5 to 13 years (All Spike).
  • 2.2.2 Senior All Lego – For participants aged 14 to 19 years (All Lego).
  • 2.2.3 Open Category – For participants aged 5 and above (All Lego).

3. Dhoyo

Figure 1.

3.1 The competition field is the area of the sumo ring (Sumo Ring), which includes the area inside the ring and the surrounding perimeter.

3.2The competition field is a circular ring with a diameter of 770 mm and a height of approximately 18 mm from the ground.

3.3 The ring has a white boundary line that is 25 mm wide. The white strip must be entirely within the circle, and the area inside the white strip is black.

3.4 The surrounding area of the ring can be any color except white and can have any shape

4.Robot Specifications:

4.1 Dimensions and Weight: Robots must fit within a 15 x 15 cm box and weigh no more than 1000 grams, including batteries and all components

4.2 The robot must be built entirely using LEGO parts or LEGO-compatible parts.

4.3 Main Controller

4.3 Robots can be built from custom-made parts or commercially available components, provided they do not damage the competition ring

  • 4.3.1 Junior All Spike Category Only Spike Prime and Mindstorms Robot Inventor controllers are allowed (as shown in Figure 2) The program must be stored in program slot number 0 only

Figure 2.

  • 4.3.2 Senior All Lego and Open CategoriesThere are no restrictions on the type or number of controllers used to build the robot. However, only one program may be stored in the controller for use during the competition. (All Controller by LEGO only)

4.4 Motor Types

  • 4.4.1 Junior All Spike Category There are no restrictions on the number of motors used. Only motors of the specified model (as shown in Figure 3) are allowed. Cutting, modifying, or altering motor wires is strictly prohibited.

Fig. 3

  • 4.4.2 Senior All Lego and Open Categories There are no restrictions on the number or type of motors used. However, all motors must be from the LEGO product line or Compatible. Cutting, modifying, or altering motor wires is strictly prohibited.

4.5 Wheels and Tires

  • 4.5.1 Junior All Spike Category There are no restrictions on the number or type of driving wheels and tires used. Only the wheels and tires shown in Figure 4 are allowed. No modifications beyond normal usage are permitted.

Fig.4

  • 4.5.2 Senior All Lego and Open Categories There are no restrictions on the number or type of driving wheels and tires used. However, all wheels must be official LEGO parts. No modifications beyond normal usage are permitted.

4.6 Power Supply Both disposable batteries and rechargeable batteries are allowed.

4.7 The robot may expand in size during the match, but only after at least 5 seconds have passed following the referee’s start signal. The robot must not launch, throw, or eject any parts or equipment during the competition. Violating this rule will result in an immediate loss for that match.

4.8 All parts must be securely attached. If any part detaches during the match, the referee will not remove it, and the match will continue

4.9 No restrictions on the colors of parts, as long as they are factory-produced colors.

4.10 Rubber bands and strings may be used only for organizing and securing wires. They must not affect the mechanical functions of the robot or interfere with the opponent’s robot.

5.Prohibited Features

5.1 Devices that interfere with opponents’ sensors, such as emitting infrared light to disrupt their function.

5.2 Components that can damage the sumo ring, including wheels coated with oil or lubricants.

5.3 Devices containing liquids, powders, or gases that can be released towards the opponent’s robot.

5.4 Any equipment that produces flames or combustion.

5.5 Mechanisms that shoot, throw, or eject parts from the robot towards the opponent

5.6 Equipment that anchors the robot to the ring, such as adhesives, sticky substances, tapes, or devices like jet propulsion systems.

5.7 If the wheels or tires are cleaned before or during the match, the cleaning process must not result in any adhesive or sticky residue that increases traction on the competition surface.

To ensure compliance, a stickiness test will be conducted:

  • The robot will be placed on half a sheet of A4 paper.
  • When lifted, the paper must not remain attached to the robot for more than 0.5 seconds.

This test will be performed only if requested by the opposing team and approved by the referee.

6.Competition Format

6.1 Each match consists of up to 3 bouts, each lasting a maximum of 2 minutes 

6.2 The first team to win two bouts (accumulating two Yuhkoh points) wins the match. If neither team achieves two Yuhkoh points after three bouts, the winner is determined based on the following criteria:

  • If both teams have one Yuhkoh point and one drawn bout, the team with the lighter robot wins.
  • If all three bouts are drawn, the team with the lighter robot wins.
  • If two bouts are drawn and one team wins the remaining bout, that team is declared the winner.
  • If the first two bouts result in no winner, a third bout is conducted. For example, if Team A wins the first bout and the second is drawn, a third bout is necessary. If Team B wins the third bout, the winner is decided by weighing the robots; the lighter robot’s team wins.

6.3 The competition follows a double-elimination format. A team is eliminated after losing twice. Winning teams advance to the next round, continuing in a knockout format until the champion, first runner-up, and second runner-up are determined.

7.Starting the Match / Restarting / Ending the Match

7.1 When the referee gives the signal, the competitors must be present at the competition field together. 

7.2 The referee will place a boundary marker on the competition field, dividing the ring into four sections. Robots will be positioned in opposite sections within the designated area, with at least part of each robot touching the white boundary line, as shown in the reference image. 

7.3 First Round Setup A coin toss or other random selection method will determine placement order. The team that loses the coin toss must place their robot on the field first, following the placement rules in Section 7.2. The robot may face any direction toward the opponent. The team that wins the coin toss will then place their robot on the field afterward. Once placed, robots cannot be moved or repositioned.

7.4 Once the signal is given, the competitor must press the start button only once to activate the robot. The robot must remain completely stationary for at least 5 seconds after the referee’s signal before beginning any movement.

7.5 From the second round onward, the team that won the previous bout places their robot on the field first, behind the Shikiri line, facing any direction towards the opponent. After that, the team that lost the previous bout places their robot on the field.

7.6 The match will be stopped and restarted only when announced by the referee.

7.7 The match officially ends when the head referee makes the announcement, and the competitors remove their robots from the field

8.Yuhkoh Points

8.1 A team earns 1 Yuhkoh point when 

  • 8.1.1 One team successfully forces any part of the opponent’s robot to touch the ground outside the sumo ring (i.e., the surrounding area). The team that achieves this first earns 1 Yuhkoh point.
  • 8.1.2 Any part of the opponent’s robot touches the ground outside the sumo ring by itself. In this case, the opposing team earns 1 Yuhkoh point.
  • 8.1.3 A robot stops functioning or fails to make any movement progress for 5 seconds.

8.2 If the robot is still on the boundary line of the sumo ring, no Yuhkoh point is awarded, and the match continues.

8.3 The Match Will Be Stopped When

  • 8.3.1 Both robots are locked together or stuck without any movement for 5 seconds.
  • 8.3.2 Both robots move in repetitive patterns, such as continuously moving back and forth, spinning in place, or circling for 5 consecutive seconds. If they also stop moving completely, it is considered a lack of movement progress. However, the referee may extend the time limit to 30 seconds in such cases.
  • 8.3.3 If any of the above situations occur to one team’s robot, the opposing team earns 1 Yuhkoh point. However, the referee may extend the time limit to 30 seconds before awarding the point.
  • 8.3.4 If both robots touch the ground outside the sumo ring simultaneously and it is unclear which robot touched first, the referee will declare a rematch.

9. Violations

9.1 A competitor who insults or disrespects the opponent, whether through words, actions, or by programming the robot to produce sounds, display messages, or exhibit gestures that are offensive or derogatory, will be disqualified.

9.2 Entering the sumo ring during the match or using any equipment inside the ring is prohibited, except when retrieving the robot after the head referee announces a Yuhkoh point or during a match pause.

9.3 Throwing or placing any parts or equipment into the sumo ring is not allowed.

9.4 A competitor who violates the provisions stated in sections 2, 4, and 5 will be penalized.

10.Penalties

10.1A competitor who violates the rules outlined in Sections 9.1, 9.2, 9.3, and 9.4 will be immediately disqualified. The opposing team will be awarded 2 Yuhkoh points, resulting in an automatic loss for the offending competitor. The violator has no right to appeal the decision.

10.2 If a team supervisor is involved in any rule violation, all teams under their supervision will be disqualified from the competition

11. Accidents During the Competition

11.1 A competitor may request to pause the match if their robot experiences an accident that prevents it from continuing.

11.2 If an accident occurs that prevents a team from continuing the match, the referee will determine which team caused the accident. The responsible team will be declared the loser. If the cause cannot be determined, the team that is unable to continue will be declared the loser.

11.3 The referee and officials will review the situation, but the decision-making process must not exceed 5 minutes

11.4 In cases where Section 11.2 applies and the team that did not cause the accident is also unable to continue, they will be awarded 2 Yuhkoh points, securing a victory. If the team already has 1 Yuhkoh point, they will receive 1 additional Yuhkoh point to win the match.

Awards

1.Champion (1 team) – Receives a trophy and a certificate of achievement.

2.First Runner-up (1 team) – Receives a trophy and a certificate of achievement.

3.Second Runner-up (1 team) – Receives a trophy and a certificate of achievement.

4.Third Runner-up (1 team) – Receives a trophy and a certificate of achievement.

5.Fourth Runner-up (4 teams) – Each team receives a trophy and a certificate of achievement.