Gauche the Cellist
This is the 1963 stop-motion animation adaption of Kenji Miyazawa's story, directed by Matsue Jimbo. It tells the tale of a young cellist named Gauche who, through the help of mischevious animal spirits, is able to overcome his faults, and give a wonderful performance at his upcoming concert. It's a sweet, popular story that has also been adapted into a longer (roughly 1 hour long) picture by Isao Takahata, producer and director for Studio Ghibli (his adaption of Gauche, however, is not a Ghibli film). I hold this particular translation in high regard as it was created by a friend of mine who was once very dear to me, who I still remember with immense fondness.Click here to view the film on YouTube. With a runtime of just 18 minutes and 35 seconds I'm sure you can make time to watch it. :-)
Alternatively, you can watch or download it from this Mega link. It is only 69.7 MBs.