Editing Robot-sumo (section)

==Rules and Classes==
The principle of a robot-sumo fight consists of two robots competing to push the opponent out of the dohyō. The arena is usually painted with a main color with a contrasting color used to paint a line in the edge (usually, black as the main color and white as the border line color).<ref name=":4" />
[[File:Robot-Sumo Arena-Douhyo.png|thumb|A sketch of a typical robot-sumo arena/dohyō from the All Japan Tournament. The brown lines in the center are called ''shikiri-sen'' ( 仕切り線) and limit the robots initial positioning.]]
Robot-sumo is usually divided in Autonomous (Auto) category, for robots that operate autonomously, and Radio-controlled (RC) category, for robots operated by a person.<ref name=":4" />

In general, the rules may vary in some details from tournament to tournament (arena specifications, starting positioning, handling of exceptions, ...) especially in tournaments of a more educational nature, held in educational institutions as a didactic activity. High level competitions tend to follow standardized rules, such as the rules from [[Robot-sumo#All Japan Robot-Sumo Tournament|All Japan Robot Sumo Tournament]] <small>[<nowiki/>[[:ja:全日本ロボット相撲大会|jp]]].</small>

For example, in FUJISOFT tournaments, matches are typically a series of 3 rounds, with the winner being the one who gets the most round wins. A round usually consists of (1) Positioning, (2) Preparation, and (3) Fight proper. In initial Positioning, a judge signals each operator to position each robot at the same time within the competition's permitted positioning limits. The judge then allows each operator to Prepare to select routines and strategies (in the case of the Auto category) or prepare the remote control (in the case of the RC category). To begin the Fight proper, the judge signals the start of the round according to the competition rules, and the winner of the round is the robot that pushes the opponent out of the arena. In the [[Robot-sumo#All Japan Robot-Sumo Tournament|All Japan Robot Sumo Tournament]] <small>[<nowiki/>[[:ja:全日本ロボット相撲大会|jp]]]</small>, the judge, at the start of a fight, usually announces "Hakkeyoi nokotta" (はっきよい 残った), which can be imprecisely translated as "Ready? Go!".<ref>{{Cite web |title=outc0000.html |url=https://www.fsi.co.jp/sumo-e/out/outc0000.html |access-date=2024-12-31 |website=www.fsi.co.jp}}</ref>[[File:All japan 2018 preparations.jpg|thumb|330x330px|Competitors preparing the robots before a Mega Sumo fight at All Japan Robot-Sumo Tournament 2018.]]FUJISOFT also requires the usage of a standardized remote controller for the judge in Autonomous category in the [[Robot-sumo#All Japan Robot-Sumo Tournament|All Japan Robot Sumo Tournament]] [[:ja:全日本ロボット相撲大会|<small>[</small>]]<small>[[:ja:全日本ロボット相撲大会|jp]]]</small>  and in its qualifiers Overseas Tournaments, so the judge may control the start and the stop of the robots' movements.<ref name=":4" /> This remote controller uses infrared light with the following specifications: wavelength of 950 nm, service frequency: 38-40 kHz, and any [[Sony]] brand remote control can be used for the signal. The activation process works with 3 states: Key 1: Ready; Key 2: Start; Key 3: Stop.

Competitions are usually divided into different weight and size classes. The main standardized classes adopted worldwide are Mega Sumo, which is the original robot-sumo class, and Mini Sumo, the most popular variant.<ref>[http://robogames.net/rules/all-sumo.php Unified Robot Sumo Rules (English)]</ref> Though classes have size limits, robots are usually allowed to expand once the fight starts.<ref name=":4" />

=== Mega Sumo ===
Mega Sumo or Sumo 3kg class, also called Standard Class, or simply Robot-Sumo, is the original class created by FUJISOFT. It is currently the most important class and considered the main event of robot sumo competitions.
[[File:|thumb|350x350px|A clash between Mega Sumo Auto 獅子奮迅, from Japan (in the left) and Galena, from ThundeRatz <small>[<nowiki/>[[:pt:ThundeRatz|pt]]<nowiki>]</nowiki></small>, Brazil (in the right) at the All Japan Robot-Sumo Tournament 2024. Magnets allow robots to move at high speed with high precision and power.]]
In this class, robots are limited in weight to 3 kg and in dimensions to 20 cm x 20 cm, with no height limit. Once the fight starts, the robot is allowed to expand its dimensions.<ref name=":4">{{Cite web |title=試合のルール｜全日本ロボット相撲大会 - ALL JAPAN ROBOT-SUMO TOURNAMENT |url=https://www.fsi.co.jp/sumo/rule/index.html#page2 |access-date=2024-12-31 |website=www.fsi.co.jp}}</ref>

In this class, the dohyō should ideally be a 5cm in height circular aluminum structure with a diameter of 154 cm (+/- 50 mm), including the border line, and covered by a black cold-rolled steel (SPCC) sheet located on top.<ref name=":4" /> The dohyō is made of steel, and the use of [[Magnet|magnets]] is allowed to increase the interaction force between the robot and the arena. Because of this, many robots can achieve normal force values that surpass 100 kgf.<ref name=":9">{{Cite web |title=ThundeRatz {{!}} Stonehenge |url=https://thunderatz.org/projects/robots/stonehenge |access-date=2024-12-31 |website=thunderatz.org}}</ref>

This class is usually divided in Mega Sumo Auto (Autonomous) and Mega Sumo RC (Radio-controlled).<ref name=":4" />

=== Mini Sumo ===
In the  Mini Sumo class (also called Sumo 500g class) robots have a weight limit of up to 500 g and are limited to 10 cm x 10 cm, with no height limit. Once the fight starts, the robot is allowed to expand its size.<ref name=":4" />[[File:Mini-sumo no Brasil.jpg|thumb|Mini Sumo match.<ref>{{Cite web |title=ThundeRatz {{!}} Ônix |url=https://thunderatz.org/projects/robots/onix |access-date=2024-12-31 |website=thunderatz.org}}</ref>]]The dohyō should be a 2.5 cm in height circular wooden board with a diameter of 77 cm (including the white border line), covered by a formica laminate located on top. The arena is made of wood, and therefore the robots are not affected by the force of magnets.<ref>{{Cite web |title=Unified Sumo Robot Rules |url=http://robogames.net/rules/all-sumo.php |access-date=2024-12-31 |website=robogames.net}}</ref>

This class is also usually divided in Mini Sumo Auto (Autonomous) and Mini Sumo RC (Radio-controlled).<ref name=":4" />  

Since a Mini robot is more affordable than a 3kg robot (due to material costs and manufacturing dimensions), it is a more popular class and often considered entry-level. Because of this, it has become the most popular robot sumo class in the world.

Not an original class from All Japan Robot-Sumo Tournament, the class was added to the tournament as a test event in 2019, and officially added in 2023, introducing mini sumo to japanese builders.<ref>{{Cite web |title=第34回｜大会結果｜ここに歴史あり｜全日本ロボット相撲大会 - ALL JAPAN ROBOT-SUMO TOURNAMENT |url=https://www.fsi.co.jp/sumo/history/record/34/index.html |access-date=2024-12-31 |website=www.fsi.co.jp}}</ref>

=== Other Standard Classes ===
There are also other standardized classes in different competitions around the world.
* '''Sumo 10 kg class''': up to 10 kg, dimensions of 30 cm x 30 cm, no height limit, steel arena. Class hosted between 2004 and 2007 by All Japan Robot-Sumo Tournament, but currently discontinued.<ref name=":1" />
* '''Micro Sumo''': up to 100 g, must fit in a 5&nbsp;cm cube, wooden arena.<ref name=":15">{{Cite web |title=RoboGames Event Schedule and Rules |url=http://robogames.net/events.php |access-date=2024-12-31 |website=robogames.net}}</ref>
* '''Nano Sumo''': up to 50 g, must fit in a 2.5&nbsp;cm cube, wooden arena.<ref name=":15" />
* '''LEGO Sumo''': robots must be made entirely of [[Lego]] pieces, wooden arena.<ref name=":11">{{Cite web |last=Inatel |title=Sumô Lego - Robótica e IA - Inatel |url=https://inatel.br/robotica/categorias/sumo-lego |access-date=2025-01-03 |website=Robótica e IA |language=pt-br}}</ref>
The Micro and Nano classes are less popular than the Mini and Mega Sumo, but they are held at some relevant events such as [[RoboGames]], RobotChallenge in China, and Robochallenge in Romania.<ref name=":15" /><ref name=":27" /><ref name=":28" />

In the LEGO Sumo class, robots must be made entirely of [[Lego]] pieces.<ref name=":11" /><ref name=":29" /> This class is widely used as an educational tool in schools for teaching robotics.[[File:LEGO Sumo.jpg|thumb|LEGO Sumo match.]]
=== Minor Variants ===
Minor regional competitions might host their own classes as well. Internal competitions in schools might also create their own variants for didatic purposes.<ref>{{Cite web |title=Home {{!}} Lego Sumo Bots |url=https://www.legosumobot.com/ |access-date=2025-01-25 |website=Hackley School |language=en}}</ref>

There are also some robot-sumo events with [[Humanoid robot|humanoid robots]].<ref>{{Cite AV media |url=https://www.youtube.com/watch?v=G4WZB0KQoMg&feature=youtu.be |title=Robot Challenge 2013 - Humanoid sumo - CZ |date=2013-03-29 |last=Tomas Podrabsky |access-date=2025-01-20 |via=YouTube}}</ref>

==== Humanoid robot-sumo ====
[[Humanoid robot|Humanoid]] robot-sumo is similar to [[Robo One|ROBO-ONE]] events.<ref name=":15" /> The robots are generally radio-controlled with some degree of autonomy. The mains robotics events with humanoid robot-sumo featured are the [[RoboGames]],<ref name=":15" /> the chinese RobotChallenge,<ref name=":5" /> and the romanian Robochallenge.<ref name=":20" /> 

Since this variant involves humanoid robots, it does not follow the same principles of design from the robot-sumo created by FUJISOFT for the All Japan Robot-Sumo Tournament. This category also does not have the same prestige as the wheeled standard robot-sumo classes, such as Mega Sumo and Mini Sumo.