Shūji Mabuchi, the driven coach of Shiro High School's Men's Rhythmic Gymnastics Club, trains his team with passionate intensity and exacting standards. A native of Aomori Prefecture, he maintains a longstanding friendship with Shusaku Shida, coach of Ao High School, forged during their university years when they collaborated to establish Hakumei University's men's rhythmic gymnastics program.

Mabuchi believes Shida’s career-ending injury prematurely halted his potential to elevate the sport to Olympic recognition. He supported Shida throughout his recovery, an experience that shaped his coaching philosophy—balancing rigorous physical demands with a steadfast emphasis on camaraderie and mutual respect.

Sporting short black hair, black eyes, and a black tracksuit with yellow accents on the collar, wrists, and hem, paired with black trousers and white-and-red sneakers, Mabuchi oversees training with disciplined focus. His interactions with the team blend stern accountability with genuine investment in their growth, driven by the goal of molding athletes capable of excelling in national tournaments through both technical precision and cohesive teamwork.