All Japan Robot Sumo Tournament – Interviews (Part 1)

japan robot sumo competition
We recently had the opportunity to visit the All Japan Robot Sumo Tournament Office and meet with Takeshi Kanai (Secretary General), Masaru Ishikawa (Vice Secretary General - Chief Judges), and Akiko Tsuda (Public Relations Section). They were kind enough to share a lot of the Japanese Robot Sumo history, and gave us some surprising insights into what is actually involved.

Note: This is the first in a series of articles on Japan Robot Sumo, and is intended to provide a general overview and history. In later articles we will explore some of the strategy, tactics, and technical aspects of the competitions.

Lem: Robot Sumo is suprisingly popular and well known. Almost every general robot competition world-wide stages a Robot Sumo event, and a lot of technical colleges and universities teach robotics courses based on robot sumo. How did it all get started?

Kanai: Almost 20 years ago our chairman and CEO, Hiroshi Nozawa proposed combining Japan's national sport of Sumo with robotics. He wanted it to become a way for both students and working people to get enjoyment and be inspired by applying manufacturing to a competitive challenge.

The concept was very well received, even in the early days. The 1st annual All Japan Robot Sumo competition took place 18 years ago and had a total of 147 robots. By the time the 4th annual competition took place the number of entries had blossomed to 448.

In the 5th annual competition year, a separate category was created for Japanese technical high schools, and the number of robots more than tripled. For that year's events there were 309 robots entered by technical high school teams, and 1,228 robots entered in the general category for a grand total of 1,537 robots. Interest and participation in the competition has continued to grow fairly consistently, year after year.

japan robot sumo

Lem: Why do you think it's turned out to be so popular?

Kanai: Certainly the participation by the technical high schools has been a big factor. Although the students on each school team change regularly as they graduate, the high school principals and teachers stay and are strong supporters of the program. Also, participation in the open category is just as strong, if not stronger, than the technical high school entries every year.

A competition like robot sumo inspires people on many different levels. Of course, they would all like to win - that goes without saying, so it's a big motivating factor. There is also the learning and improving yourself aspect. People really want to demonstrate their ability, to show what they can create, both to others and to themselves.

Probably the most important factor is what we call 'monozukuri'. A literal translation is probably "thing making", but in the sense that we use the word in Japanese it also incorporates craftsmanship and the creative process. There's a level of pride and ownership that takes place when an individual or team creates their robot and competes with it. Many of the competitors find that aspect of robot sumo very compelling. In fact, some of them even compare the techniques used to design their robots with the Edo era Japanese craftsmen that created samurai swords.

Lem: I remember that Toyota's production system training says “There can be no successful monozukuri (making thing) without hito-zukuri (making people).”

With the large number of entries it would be impossible for everyone to compete at the same time. How do you coordinate everything?

japan robot sumo

Kanai: We divide Japan into nine regions, and stage regional competitions starting in early September each year. Each region is assigned a number of top positions based on proportional participation. For the technical high school classification, it's based on the number of participating high schools in the regions. In the open classification it's based on the total number of entries. For example, the top 4 robots (2 autonomous and 2 radio controlled) in the Shikoku regional competition will go on to compete in the All Japan finals. For the Kanto regional competition the top 12 robots (6 autonomous and 6 radio controlled) go on to the finals since the total number of entries in the Kanto region is much larger than the Shikoku region.

After all the regional competitions, the All Japan Robot Sumo final competition (3 kg. class) for the year is held on December 23rd at the Kokugikan Sumo Hall in Tokyo. Of all the robot entries for the year, only the top 64 autonomous and 64 radio controlled robots get to compete in the finals.

Lem: Is the competition only for Japanese entries?

Kanai: No, not at all. Of course, the technical high school classification is specifically for Japanese technical high schools. But the open classification is open to the public including foreign robots. Over the years we've had a wide range of different entries, including women, seniors, and even very young robot operators. The oldest entrant was over 70, and the youngest 'pilot' was 8 years old.


Lem: I attended last year's Kanto Regional 3 kg. class competition and the 10 kg. class final competition in Yokohama a few months ago. The robots move so quickly, and the action is so fast that it's difficult to imagine how a referee can follow a match and provide reliable judgements. Is that a problem?

Ishikawa: Yes, it's a significant challenge. As you mentioned, in some cases the match is over so quickly that if you blink you miss it. The television news cameramen often complain that they can't follow the robots in action. A referee has to be well trained and have a lot of experience before they can be officially certified.

We're lucky because over the years we've built up a strong base of experienced referees. We've made a special effort to provide information, training, and instructors so that the referees can constantly improve their judging skill and know-how. Starting in late May each year, we put on an official referee training and certification program. It's a lot of work, and a big commitment on the part of everyone involved. Still, it's proven well worth the effort. We currently have 516 certified referees here in Japan.

japan robot sumo

Lem: How do you compare robot sumo in Japan with competition robot events overseas?

Kanai: It's hard to make a direct comparison, especially since we don't have the chance to visit each other's competitions regularly. In 1998, in celebration of the 10th anniversary of All Japan Robot Sumo, we took a group of the top competitors to several of the robot events on the west coast of the United States. We got to see events and play matches with local competitors at ROBOlympics (now called RoboGames) in San Francisco and other competitions in Seattle, Portland, and Los Angeles.

All the participants had a great time and enjoyed it a lot. You can easily imagine how surprised they were to see their first combat robot competitions. They were so excited. Some of the smaller sumo ro bots were surprising also. Most of the robot sumo competitions here in Japan are either 3 kg. or 10 kg. class, so the 500 gram and smaller robots were really interesting. We hope to mount another similar overseas expedition in the future. A common interest in robotics is a great way to overcome cultural differences and facilitate communication. 

In the next article in this series, we'll dig into some of the technical background including some of the strategies and tactics used by the top Japanese robot sumo competitors.

Photo credit: All Japan Robot-SUMO Tournament Office (all screen shot images in this article.)

Related links:

FSI-All Japan Robot Sumo Tournament Website (English)

FSI-All Japan Robot Sumo Tournament Website (Japanese)


3 thoughts on “All Japan Robot Sumo Tournament – Interviews (Part 1)

  1. Those little guys can book. I didn’t realize that some were remote controlled! I figured they were all autonomous. I look forward to part two… Hopefully it will shed some light on whether the remote bots use sensors as well.

  2. M.B.,

    They are fast, and powerful – though not destructive like the Battlebots. Roughly half of the entries are remote control, but also have sensors and some autonomous capability. Pure R/C wouldn’t be effective to control a robot at those speeds since the human can’t react fast enough.

    I’ll be posting more background along with a really killer set of videos soon. After that, I’m sure you’ll really get a kick out of our upcoming coverage on the “American Robot Football” competition they stage annually here.

  3. What motors do the 3kg robots typically use? I heard that there is a fantastic motor made by a German company that goes for about $200 ea. that has become popular with Japanese 3kg robots.

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