The ring sits in the spotlight of a tense, packed auditorium and the jittery fighters await the bell at their red and blue corners.
Like any fight, there’s always the danger of a punishing uppercut or left hook. But these boxers have even more worries — like battery failure and software bugs.
The contenders are robots fighting in a special kickboxing match that’s held twice a year in Japan, a leading nation in the robotics world.
The all-for-fun event is evidence not only of an infatuation with robots here but also of the widely accepted view of robots as entertaining friends.
It’s a contrast to other nations, where robotics are increasingly being used in warfare and robots often considered creepy threats.
“For me, robots are for making people happy,” said Yusuke Sugawara, a 32-year-old engineer whose robot wore a fluffy wig and blew bubbles from a fake snorkel when people clapped. “Japanese people all love robots. Inside our hearts, we all want to make robots that we grew up watching on TV cartoons.”
Kickboxing, karate and taekwondo
Robo-One, begun four years ago to stimulate public interest in robots, is loosely based on K-1, a popular sport that combines elements of kickboxing, karate and taekwondo.
The Sixth Robo-One Contest during a recent weekend drew 90 robots running on software developed by amateurs from across Japan and South Korea to a hall in Kawasaki, southwest of Tokyo.
Unlike human boxing matches, the corner crew in these contests struggles with battery changes and, in one case, vigorously flapped handheld paper fans to cool the motors lodged in the robot’s joints in between rounds.
When a metal part fell off one robot, its owner had to tape it back into the body.
According to Robo-One rules, a robot that gets pulled, pushed or punched down must get up on its feet before the referee counts to 10 to avoid a knockout.
Shining in bright colors, the robots, mostly measuring about 16 inches (40 centimeters) tall, look like fancy toys and sport comic-book names like Typhoon SP, Dynamizer2 and Majingaa.
They sometimes become entangled and tumble off the ring together onto the cushions on the floor. A fall from the ring counts as two knockdowns, with three knockdowns resulting in a loss just like a knockout.
With robots, the count to 10 also starts when a machine freezes in mid-action on its feet. If it collapses by accident on its own and can’t get up before the count to 10, that’s a knockout as well.
“The technological advances have been amazing over the years,” says Naohiro Hayaishi of robot-maker and Robo-One participant Vstone, who has attended the matches from their inception. “These days, the robots really look like they are fighting.”
Hayaishi recalled that some robots barely managed to move in earlier contests.
Robotic agony and ecstasy
These days, they manage to even pander to the audience, getting down and banging the floor in agony when they lose, or raising their fist in the air and waving to the crowd in victory.
One move that’s a relatively recent addition to the robots’ repertoire is turning somersaults and crashing into the opponent to bring it down.
Polished looks, smooth moves and autonomy are key qualities factored into the judging. Sloppily hanging cables are a no-no.
The robot’s creators stand by the ring with their wireless radio controls or laptops, some alone and others with assistants or their children.
A special guest was Go Nagai, a comic-book artist and a beloved star with Robo-One fans, who were thrilled to get his autograph.
Kits for remote-control robots are on sale in Japan, but most participants designed their own, cutting metal parts and coming up with their own programming. A basic programming for robots is available for free from Robo-One.
“It’s fun to see something we made move,” said Masayoshi Morishita, a 15-year-old high-school student, who took part in Robo-One with his classmates.
The fight money isn’t stingy at Robo-One, which has drawn corporate sponsors, including major Tokyo-based toymaker Bandai Co and 20th Century Fox. Its science-fiction thriller movie “I, Robot,” is soon to be released in Japan.
This year’s winner, the 11-pound (5-kilogram) Humanoid Project from Kyushu University, outmuscled rivals, collecting $9,000. The runner-up was awarded $1,800.
“It’s exciting to see your own ideas take shape in an actual robot,” said Toshinobu Koga, 24, one of the students behind the winning robot. Another team member took a robot to an interview and landed himself a job at a major electronics maker, he added.
One of the most exciting moments of Robo-One is the Rumble, when eight robots enter the ring at once, all trying to knock everyone else off the ring.
The last machine standing is the winner.
When more than one is left after five minutes of chaotic whirring and clanging, the crowd decides by applause which gladiator robot wins.