Piano ga Nakereba Tada no Gomi

Japan, has a piano-playing population of 1.6 million people, one of the largest in the world, of which fewer than 10 are professional pianists who can make a living from concerts. Kanade Tendo, a fifth grader, was the best piano player in Japan. He was not good at all in studies or athletics, but that was okay. He was the best piano player in Japan, and that alone made him the center of attention and silenced criticism, even from the teacher. Then one day, a transfer student named Koharu Sakura arrives. As often happens, she became the target of bullying in class. Kanade, who is assigned to teach her piano by chance, notices a certain talent in her.

A year later, something happens that will reverse Kanade and Koharu's positions.

(Source: ComicWalker, translated)