The character Minoru Minorikawa was introduced in 2004 with the release of 3-Nen B-Gumi Kinpachi Sensei: Densetsu no Kyoudan ni Tate!. Debuting in Episode 8, he appears as a reporter for a newspaper, who is looking into the unresolved suicide of a middle school girl named Chiharu Fuyutsuki from 5 years ago (6 by the end of the game). He works alongside the protagonist, who was Chiharu's teacher back then, to uncover the truth behind her suicide.

In 428: Shibuya Scramble, Minorikawa appears once again, but instead of being a minor late-game character, he became one of the leading protagonists of the game. In this game, he is now a freelance journalist who is attempting to help his old friend Toyama (who used to work at the same newspaper company) in gathering enough stories for Toyama's next magazine issue. During the course of 428, Minorikawa begins reminiscing to his investigation of Chiharu's suicide, with the game making a handful of references to the events of Kinpachi Sensei.

However, the English localization for 428 contains a mistranslation within the reference to Kinpachi Sensei, likely because the latter has never been released in the West. The in-game TIPS for Chiharu Fuyutsuki states that "6 years from now", Minorikawa would solve the mystery behind Chiharu's suicide, while the original Japanese makes it clear that it should be "6 years after this incident." The mistranslation would suggest that Kinpachi Sensei is set years after 428, even though this contradicts Minorikawa's journey from working at a newspaper to working freelance.