Donkey Kong no Ongaku Asobi (Donkey Kong’s Fun With Music) is an unreleased 1983 Famicom educational video game that starred the cast of the original Donkey Kong series with the newcomer Donkey Kong Jr. This game is meant to teach players music. They were planned to released this on Famicom in 1983 but they only released two educational games, Donkey Kong Jr. Math and Popeye no Eigo Asobi and cancelled this game for unknown reasons. Donkey Kong’s Fun With Music had only been announced in 1983 in a Japanese gaming magazine.
No prototypes or any other information has surfaced. Only four screenshots of the game exist.
http://www.mariowiki.com/Donkey_Kong_no_Ongaku_Asobi Super Mario Wiki article.