Drama Special Season 1: Pianist

Oh Je Ro is a musical genius who had always dreamt of learning the piano, but had to work in a piano factory as tuner instead of going to school in order to support his sick father. He had despaired of ever being given a chance to learn and thought the name his father gave him sounded like "Oh, Zero", signifying his lack of hope in the future. This changes when he meets an elementary school teacher, Yoon In Sa, and begins a delicate love story with her.
(Source: DramaWiki)