Yuuki Mitani

Mitani is cynical, quick-tempered and defensive. He dislikes being lectured and reacts badly when other people try to dictate how he should play.

His cheating comes partly from enjoying the control it gives him over unsuspecting opponents. Being subjected to the same kind of manipulation forces him to experience the humiliation from the other side.

Mitani nevertheless becomes attached to the Haze team. That attachment makes Hikaru's decision to leave school competition for the insei system feel like a personal rejection rather than merely a career choice.

Mitani is naturally talented at Go and considerably stronger than Tsutsui when introduced. He does not need to cheat to be a competent school-level player.

His style can be aggressive and disruptive. Against stronger opponents, he sometimes tries to accelerate the pace and create complications rather than allow them to settle comfortably into superior positional play.

His ability is still well below the upper insei and professional level. Hikaru's rapid improvement eventually creates a substantial gap between them.

Hikaru searches for another player so Haze can field a complete team and discovers Mitani playing Go for money. Learning that Mitani cheats creates a conflict over whether he should be invited into the club.

Dake is brought in to teach Mitani a lesson by beating him at his own methods. The experience does not instantly change Mitani, but Hikaru continues trying to bring him into legitimate competition.

Mitani eventually joins Haze and becomes invested in the team. When Hikaru decides to become an insei and can no longer represent the school, Mitani takes the decision personally. Although he remains with the club, the easy friendship he and Hikaru briefly developed never fully returns.

Hikaru Shindou recruits Mitani for the Haze Go Club and refuses to give up on him after discovering his cheating. Mitani later feels abandoned when Hikaru Shindou leaves school competition to become an insei.

Kimihiro Tsutsui initially distrusts Mitani because of his cheating but eventually accepts him as part of the Haze team.

Akari Fujisaki becomes another member of the Haze Go Club alongside Mitani.

Dake deliberately turns Mitani's cheating methods against him in a high-stakes game intended to teach him a lesson.

Mitani's older sister, Mitani no Ane, works at the Internet café that Hikaru later uses for online Go.