Kōsuke MasudaKōsuke Masuda.

Masuda Kōsuke Gekijō: Gag Manga Biyori (Japanese: 増田こうすけ劇場 ギャグマンガ日和, Hepburn: Masuda Kōsuke Gekijō Gyagu Manga Biyori; lit. 'Kosuke Masuda Theater: Good Day for Gag Manga'), or simply known as Gag Manga Biyori, is a Japanese manga series written and illustrated by Kosuke Masuda. The series features a hyperactive, random, and nonsensical style that revolves around various plots and characters throughout. It started in Shueisha's shōnen manga magazine Monthly Shōnen Jump in the January 2000 issue.