Kouki Shiroyama

Shiroyama is competitive and comfortable within Hokuo's confident team culture. Like the club's other members, he takes pride in representing a school with a strong competitive record and expects Hokuo to contend seriously in team tournaments.

His distinctive spiral hair accessories give him an immediately recognizable appearance, but the story devotes substantially less individual attention to his personality than to Hokuo's leading players.

Shiroyama is a trained competitive karuta player capable of representing Hokuo Academy in official team competition. Selection for the school's lineup places him within a club whose practices and internal competition produce consistently strong players.

The series does not establish a distinctive signature technique for Shiroyama comparable to Sudo's psychological pressure or other major players' specialized styles. His importance lies instead in Hokuo's roster depth and collective experience.

Shiroyama appears during Mizusawa's encounters with Hokuo Academy, particularly in the Tokyo high-school team competition. Hokuo begins as the established regional power that Chihaya's newly formed club must challenge.

His presence helps establish that Hokuo cannot be reduced to one or two star players. Mizusawa has to defeat an experienced five-person team rather than simply overcome Sudo or Retro individually.

Shiroyama continues to appear around Hokuo's competitive activities as the rivalry between the schools develops from a one-sided matchup into recurring competition between familiar opponents.

Akihito Sudo is Hokuo's strongest senior player during Shiroyama's early appearances. Kouki Shiroyama competes within the team environment shaped by Akihito Sudo's demanding presence.

Hiro Kinashi is another prominent Hokuo teammate. Kouki Shiroyama and Hiro Kinashi both represent the school's established karuta program in team competition.

Chihaya Ayase and the Mizusawa players become recurring opponents of Shiroyama's Hokuo team as the two schools compete for Tokyo's leading position.