“What makes SSL so fun is the sense of accomplishment you get when your robots score,” says Hirohashi, who first decided to participate in the RoboCup when he was a student at Ritsumeikan Moriyama Junior High School. His interest in SSL was sparked after watching a robot soccer match at RoboCup and trying his hand at making a soccer robot from a kit provided by the Sci-Tech Club, a science and technology student club that he belonged to. “I was very attracted to the idea of being able to play soccer with an original robot that I had customized with numerous mechanisms and sensors," recalls Hirohashi, who began working on everything from design and production to programming in his third year of junior high school. He continued to participate in the RoboCup Junior Soccer League until his third year of high school. That was the year in which he and his teammates from the Ritsumeikan Moriyama High School Sci-Tech Club competed in the RoboCup Junior World Championships, finishing second place overall.

Hirohashi's enthusiasm did not wane even after advancing to Ritsumeikan University. "The age limit for RoboCup Junior is 19 years old, so once you go to university, you have to switch to the senior division. In the senior division, the soccer field is larger and there are more robots, which makes it much more challenging, but I wanted nothing more than to master soccer robots,” he explains. This led Hirohashi to join Ri-one, a student organization that aims to be number one in Japan and the world at RoboCup.

At that time, however, Ri-one did not have a Small Size League (SSL) team for soccer robots, so in his second year, Hirohashi decided to start a team by himself. He had trouble finding other members because the timing coincided with the beginning of the COVID-19 pandemic. “We were holding information sessions for students who wanted to join our club via Zoom at that time, so we had to be creative with how to convey the fun of SSL through the screen. We created a promotional video of a robot actually playing soccer. We were very particular about the production so the video would leave a powerful impact. The speed of the ball in robot soccer is much faster than in soccer played by humans, so we thought about how to showcase that," explains Hirohashi. Thanks to this, the club attracted several new members from the information session, and the SSL team launched with a group of seven.

Looking back on the early days of this new team, Hirohashi said it was an extremely busy time. Since everyone else was new to SSL except for Hirohashi, he had to go around teaching each of them all the hardware, software, and circuits necessary to build robots, and he had to oversee the entire project including repairs and checking. In order to complete six elaborate robots by the time of the competition with only seven people, Hirohashi also had to divvy up duties among the team members and work out a detailed schedule for fabrication. “This experience really strengthened my management skills. In the second year after starting the team, we attracted even more members, so I made the bold decision to assign the younger students I had trained the previous year to lead their respective groups," Hirohashi recalls.

The team has participated in the RoboCup every year since its first year, and as each member's technical skills improved, so did the team’s performance. In 2021, in their first appearance at the RoboCup Asia Pacific-Aichi SSL, the team only managed one win and finished in fifth place, but from there they steadily improved their abilities, finishing fifth in the World Championship the following year and third in both the Japan and world championships in 2023. Then, in July 2024, Hirohashi finally achieved his long-cherished goal of winning the world championship.

Mr. Hirohashi discussed the secrets of his team's strength as follows. “To beat the other teams, we needed to have unique new mechanisms and sensors. It was difficult to develop, but my team equipped the robots with sensor cameras to recognize the ball. It is very rare for the robots in the league to be equipped with built-in cameras.” According to Hirohashi, the team was able mount each robot with a camera because they focused their efforts on miniaturization. “We design and make our own hardware and circuitry by hand, using almost no off-the-shelf products. We even thought about space and devised a way to make it possible to mount various mechanisms on a robot of a specified size," he remarks, adding that one of the reasons for their success was the originality of their robot design.

The fact that they had a rival was also a big driver. It was a team from a technical college in another prefecture that had been competing against Hirohashi since his days at RoboCup Junior, and they advanced to the senior division at the same time as him. “They had cool robots and excellent technology in each and every mechanism. We saw each other as rivals, and I think this inspired us both to take our technology to the next level," he recalls.

In his last year as a student, Hirohashi fulfilled his long-held dream of winning the world championship. After graduation, he plans to work in technical development for an electrical equipment company, but he intends to continue competing in RoboCup even after entering the workforce. “I still want to work on perfecting soccer robots. When I was a student, I competed in the SSL Division B tournament at RoboCup, which is mainly for newcomer teams, but now I would like to attempt to compete in Division A, which requires a higher level of skill.”
It seems that Hirohashi’s relentless pursuit of robotics will only continue.