Tooru Itoyama

Itoyama receives limited individual characterization, with his appearances centered on his responsibilities as a baseball coach.

His handling of Aoba demonstrates practical recognition of her ability. Although she cannot officially compete in the boys' tournament structure, she is allowed to participate in practice games and remain involved with the team.

Itoyama's established expertise is coaching youth baseball. He supervises players during a formative stage before many of them enter Seishuu High School's more demanding program.

The middle-school team under his supervision develops several players who later become high-school regulars, including members across the infield and outfield.

Itoyama belongs to the baseball environment preceding Kou's high-school career. While Kou does not join the middle-school team, many of his eventual teammates already play organized baseball there.

Aoba is particularly important within this period. She practices with the boys and participates in unofficial games, allowing her pitching to develop against competitive opposition despite being excluded from official tournament play.

Aoba Tsukishima plays and practices under Itoyama's supervision at Seishuu Middle School despite being unable to enter official boys' games.

Osamu Akaishi is one of Itoyama's players and serves as a captain before moving on to high school.

Keiichirou Senda pitches for the middle-school team, while Mitani, Yashiro, Hama and Ehara also play under Itoyama before advancing to Seishuu High School.