Robot sumo wrestlers from 10 countries battled each other Sunday at Tokyo's Ryogoku Kokugikan, the Mecca of traditional sumo, in the first such event of its kind.

A Latvian team named Robotu Skola took the title in the autonomous category at the inaugural International Robot Sumo Tournament, which saw 31 sumo machines face off.

A Japanese high school team named Mirai Robo Koken from Oita Prefecture won the radio-controlled category, which saw 10 robots compete.

In the autonomous robot event, the machines had to fight on their own in a 1.5-meter-wide ring using pre-programmed movements and sensors to find their opponent and attack.

In the radio-controlled category, engineers were allowed to direct their creations remotely.

Under the contest's rules, robots must weigh no more than 3 kg and be no more than 20 cm deep or wide. They win by pushing their opponents outside the ring completely.

Many robots had a square shape, like a box, with a blade mounted on the front to assault and push their opponents out.

The battles could finish within seconds because the robots move so quickly. For the autonomous robots, it seemed critical to pinpoint the opponent's position and attack from an effective angle.

The engineering teams watched intently during the matches, and the winners didn't shy away from expressing their excitement.

"We are glad that we could win the tournament," said Masaaki Hashizume of Mirai Robo Koken, a robotics club at Oita Kogyo High School, an engineering school.

Hashizume's team won the national tournament in the morning, moving on to represent Japan in the world championship in the afternoon.

"We looked back at last year's experience and studied our rivals' robots. We also analyzed what went wrong with ours and made improvements," said Hashizume, adding that they worked on a blade to pick up opponents and programmed the robot so it could make small turns more smoothly and track fast-moving opponents.

"I feel very happy to win this championship," said Einars Deksnis, 25, from Robotu Skola, who won the contest for the autonomous category.

Deksnis, who competed in a trial international match in Japan last year, said he, too, learned from past mistakes and made adjustments.

Organized mainly by Fujisoft Inc., a Yokohama-based system engineering firm, Japan's annual robot sumo competition started in 1990 to boost the motivation and technical expertise of engineers.

Similar events have caught on in other countries, so the organizers decided to inaugurate an international tournament this year.

Other teams hailed from Brazil, Mexico, Poland, Romania Spain, Turkey, Austria and Columbia.