Kantai Collection (“Combined Fleet Collection”), abbreviated as KanColle, is a Japanese free-to-play online card game developed by Kadokawa Games. The game was launched on April 23, 2013. As of April 2014, the game is available in Japan only and has 1.9 million registered players. Various media including multiple manga series and light novels have been released, in addition to an officially licensed tabletop role-playing game. A television anime series and PlayStation Vita game have been announced.
(Source: Wikipedia)

The main reason for its popularity is most likely the appearance of the “battleships”, all being cute and sexy female characters. With more and more artists creating fanart, music re-arrangements and other art, KanColle is the next big thing in the Doujin scene.

On MikuDB you will find various KanColle music albums, have a listen!