Hidarite no Tame no Nijuusou

Shu's had a rough start to life, and doesn't think he has much of a future—until fate brings him together with talented young pianist and fellow student Akari Yuzuki, the girl with the "Angelic Left Hand" for one high-flying adventure. But when tragedy cuts their relationship short, Shu realizes he must find a way to live for them both...and realizes that something is no longer quite right with his own left hand...

(Source: Kodansha USA)