Susumu Karasawa, a former middle school judo champion, shifts to baseball in high school after impulsively joining the team to comfort a girl distraught over its failures—later revealed as the coach’s daughter. Though his initial romantic motives fade, his commitment to the sport deepens, anchoring him to the team. As right fielder wearing jersey number 9, a symbol of collective purpose, his judo-trained strength sharpens his powerful throws, blending physical prowess with tactical precision.

Known for his boisterous humor and impulsive antics, he lightens tense moments, such as his exaggerated shock at a teammate’s eccentric train behavior. Behind the comedy lies a shrewd mediator: he confronts peers over conflicts like stolen undergarments and bridges rifts between teammates and their families, reinforcing trust.

While romance remains peripheral to his arc, his mischievous yet supportive presence counterbalances the team’s intense ambitions. His journey traces a shift from seeking fleeting approval in judo to embracing baseball’s demands, embodying the narrative’s core themes—how individual growth intertwines with team solidarity, transforming casual participants into devoted collaborators striving for shared triumph.