Robot-sumo

Robot-sumo (Japanese: ロボット相撲) is an engineering and robotics competition in which two robots attempt to push each other out of a circular arena, in a similar fashion to the sport of sumo. The robots used in this competition are called "sumo robots", "sumobots" or simply "sumos". Competitions typically involve autonomously operated wheeled mobile robots. The engineering challenges are for the robot to find its opponent (usually accomplished with infrared or ultra-sonic sensors) and to push it out of the dohyō. A robot should also avoid leaving the arena, usually by means of a sensor that detects the edge. The most common mechanical design is to use a wedge with a blade at the front to lift the opposing robot and push it more easily.

Robot-Sumo originated in Japan in 1989 when FUJISOFT Inc. [jp] organized an experimental robot-sumo tournament, which would later be established as the All Japan Robot Sumo Tournament [jp](Japanese: 全日本ロボット相撲大会 zen'nippon robotto sumou taikai). Since 1998, FUJISOFT has collaborated with more than 30 countries, and robot-sumo has spread and has been one of the most popular robotics competitions in the world, such as in Europe, Mexico and Brazil, with a total of 80,000 people around the world actively developing sumo robots. The All Japan Robot-Sumo Tournament has been hailed as the "World Robot-Sumo Championship". In August 2026, however, FUJISOFT announced that it would cease organizing the event, with the 2026 edition being the final tournament. Robot-sumo competitions still hold amateur status, though high-performance competitions (events contested between technical students, universitarians and graduated engineers hobbyists) require highly complex engineering projects. Robot-sumo is also often used as an educational tool of engineering, robotics and electronics for simpler protoypes in schools and undergraduate levels. Sumo robots design has also been the subject of studies and research of academic nature as well.

History Robot-Sumo began in Japan with the All Japan Robot Sumo Tournament [jp] organized by FUJISOFT Inc. [jp] for the first time in 1989 as an experimental tournament, with 33 participants. The first official edition was established in 1990, and, since then, this tournament has been held annually in Tokyo. The competition began with an idea from the president of FUJISOFT Inc., Hiroshi Nozawa, whose goal was to promote his company and recruit excellent human resources. But above all, it was because of his desire to give a dream to the younger people who are responsible for the future of his country, and because of the desire to create an environment to improve the quality of "Monozukuri" in Japan. Initially, Robot Sumo only included the class that would be later known as Mega Sumo or Sumo 3 kg class. In 1992, the FUJISOFT tournament was held at the Ryōgoku Kokugikan, where the tournament is still held today. In 1998, the tournament had 2,929 participants. Also in 1998, the first Robot-Sumo competition was held outside of Japan, at the ROBOlympics (later renamed RoboGames), one of the largest robotics events at the time, held in the USA. This event helped popularize sumo competitions around the world and led to the creation of categories derived from 3 kg class, such as Mini Sumo (500g class), LEGO Sumo, among others, which further popularized the category as a whole, leading to the emergence of many competitions around the world, such as in Mexico, Europe, and South America. The exact origin of those derived robot-sumo classes is uncertain, however there are footage of Mini Sumo RC from 2002 at the RoboGames. In 2004, at the 15th edition of the All Japan Robot-Sumo Tournament, the tournament introduced the 10 kg class, but it would be discontinued in 2007. In 2008, RoboCore organized the first official national robot-sumo tournament in Brazil as part of the expansion of the national robotics competition "Winter Challenge", originally a robot combat focused event mainly contested by universitarian teams from the country. In this competition, Sumo 3 kg Auto, Sumo 3 kg RC and Sumo LEGO classes were held. Until 2019, the Winter or Summer Challenge was the biggest robotics event in Brazil and Latin America, considered the "Brazilian National Robotics Championship" by many. Also in 2008, with the increasing worldwide popularity of robot-sumo, FUJISOFT held for the first time an edition of the All Japan Robot-Sumo Tournament with international competitors, from United States, Mexico and Singapore. Since then, the All Japan became a world championship, with the participation of overseas competitors as “Overseas Representatives”. In 2010, the Robochallenge, in Romania, hosted a robot-sumo event for the first time. In 2013, FUJISOFT held the first official edition of the International Robot-Sumo Tournament (Japanese: 世界大会 sekai taikai), separating from the Japanese national All Japan competition (Japanese: 全国大会 zenkoku taikai), with only the best Japanese (champions, and later runners-up) advancing to the world tournament, with both tournaments being held in the same day, in sequence. In this edition, tournament champions or national representatives from Austria, USA, Baltic States (Estonia, Latvia and Lithuania), Turkey, Mexico and Ecuador participated as overseas representatives. The Auto tournament had 16 robots, and the RC tournament, 8 robots, in 2013.

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