The Forest of Wool and Steel by Natsu Miyashita
It was life-making. Tomura is startled by the hypnotic sound of a piano being tuned in his school. It seeps into his soul and transports him to the forests, dark and gleaming, that surround his beloved mountain village.
From that moment, he is determined to discover more. Under the tutelage of three master piano-tuners – one humble, one jovial, one ill-tempered – Tomura embarks on his training, never straying too far from a single, unfathomable question: do I have what it takes?