Blue Box Manga Series 10-Book Collection Set (Vol.1 to Vol.10) by Kouji Miura

The story centers on Taiki Inomata, a dedicated member of the boys' badminton team at Eimei Junior and Senior High School. Every morning, he arrives early to practice in the gymnasium, where he admires Chinatsu Kano, an older student and the star player on the girls' basketball team.

​Taiki's feelings deepen through their shared work ethic, but his life changes dramatically when Chinatsu's parents move abroad, leading her to live with Taiki's family. As they share the same roof, Taiki must balance his growing affection for Chinatsu with his goal of qualifying for the national sports tournament.