The Perfect World of Kai (2007)

Amamiya Shuuhei moves from Tokyo to the countryside because of his grandmother's bad health. His father is a famous pianist and Shuuhei has taken strict piano lessons since he was very young, aspiring to follow in his footsteps. In school, he is teased by his classmates and is dared to play the piano in the forest. This piano is said to be cursed: if you play it, no sound will come. After school, Ichinose Kai, a boy in the same class, takes Shuuhei to the forest. When Shuuhei tries to play he fails, but Kai plays a wonderful song. This is the beginning of a strong friendship, and a story of two very different boys developing their skills as musicians.