Sumo Wrestling Micro-Mechanism Competition

Competitions for wired and wireless machines are conducted separately.


This competition aims at developing mechanisms having superior actuator technology, which are tested by physically coming into contact with each other in a competition of power and techniques.
Competitors with wired and wireless machines compete separately in this tournament, and one winner from each division is decided. The limits of size and weight have been eased for wireless machines. Self-propelled machines may enter the competition.

Important notice
This time,the regulation (l) "Do not use uncontrollable sticking function at your machine, to stick to the opponentfs machine and to drop off the ring together." is added.


The area of the competition (ring) is a circular plastic board 200 mm in diameter and 10 mm thick covered with patterned Kent Paper, as shown in Fig. 5. A machine wins the match if it pushes or drops its opponent out of the ring. A machine also wins a match if it knocks over the opponent or forces it to fall on its side. A machine loses a match if any part of it the main body touches the board outside the ring. A machine does not win by simply lifting its opponent. The time limit for one match is one minute. If there is no winner within this time, referees will decide the winner to be the machine that attacked more aggressively. Namely, the machine that has not moved actively will lose the match.


(a) The size and weight limits are different for wired and wireless machines. Wired machines, including all appendages (e.g., the hands and arms), must fit in a box of size 15 mm ~ 15 mm ~ 20 mm at the start of the match. However, machines may have larger dimensions after the match starts. The weight of the machine must not exceed 20 gf. Wireless machines must fit in a box of size 20 mm ~ 20 mm ~ 30 mm, and their weight must not exceed 45 gf. There are no regulations on the movement of machines; they can run, crawl, and jump.

(b) The referee calls two operators. The timing will start when both operators have assembled. Contestants should place their machines within their starting area when the referee says gon your marks.h Any posture and direction of the machine is acceptable provided the centroid of its horizontal projection is positioned within the starting area. However, machines must not exceed the size limit when placed in the starting area before the referee says ggo.h The referee will says greadyh then ggoh two seconds after confirming that both machines are appropriately placed. Minor adjustments can be made to the machines even after the referee says gon your marks,h during which the timing is continued.

(c) Machines equipped with a deformation mechanism are not allowed to start if they exceed the size limit before the referee says ggo.h Machines will be disqualified if they do not start within one minute after the start of timing or if they commit three false starts. (In other words, you may start your machine up to three times.)

(d) To minimize false starts, the referee will confirm with both operators that they are ready to start after their machines have been placed in their starting area and then say greadyh and ggoh two seconds after the confirmation. A false start is defined as follows.
  • When a machine equipped with a deformation mechanism exceeds the size limit before the referee says "go."
  • When an operator starts operating the machine before the referee says ggo.h
When the referee decides that a false start has occurred, the match will be immediately restarted.

(e) You must not damage the ring intentionally.

(f) You must not attack the opponentfs machine with the purpose of totally destroying it such as by using edged tools, strong acidic liquid, or other means.

(g) Some parts may be separated from the machine. In this case, the largest part is regarded as the main body of the machine. Even if a smaller part is turned over onto its side or touches the board outside the ring, this will not lead to the machine losing the match.

(h) For wired machines, you may supply energy or send control signals through lead wires or flexible tubes from an external device. However, these wires and tubes must not be used for any other purpose. Such tubes and wires must extend above the machine and must not rest on the ring. If the cables become entangled and the referee judges it difficult to continue the match, the referee will stop the match, and the match will be restarted after the cables have been disentangled.

(i) When using commercial radio apparatus, you must take great care to ensure that the signals of your machine do not interfere with those of your opponentfs machine. Matches will not be suspended owing to the interference of radio signals. Operators should pay close attention to signal interference, for example, by keeping their controllers switched off except during their own match. Operators intentionally jamming the radio signals of an opponent will be disqualified.

(j) When a referee thinks it difficult to decide the winner, the referee together with judges discuss and restart the match again in most of the cases. Instant replay or judging by video is not acceptable because above recording requires close up, that often causes bothering machine operation or causes sensor malfunctioning. And do not take video from the area where we prohibit to enter.

(k) If you have a question about the judging results, please ask before the next match.

(l) Do not use uncontrollable sticking function at your machine, to stick to the opponentfs machine and to drop off the ring together.

In addition to the competition itself, a Concept Prize, a Technical Prize, and an Artistic Prize will be awarded. Please do not miss this opportunity.

Fig. 5 Ring for sumo wrestling micro-mechanism competition
(Wired and wireless machines compete in separate tournaments although this figure shows a fight between a wired machine and a wireless machine.)

(Click to view a larger picture.)