Kids on the Slope

It is summer 10 years ago. Kaoru transfers to a new school and has a fateful encounter with the school's terrifying bad-boy Sentaro. They bond over jazz and Kaoru finds that he's oddly drawn to the rough-mannered Sentaro. After jamming on the piano and drums and spending time with Sentaro's childhood friend Ritsuko, Kaoru falls for Ritsuko but finds out she likes Sentaro.
(Source: JFDB)