Short: (
Type subgenre) This category contains titles whose playing time is unusually short as compared to the length of standard anime episodes (which are roughly 20 minutes plus intro & trailer).
Music: (
Story/Location) If a title deals with music as significant element of the story, and / or the lead characters are musicians and this is significant for their role in the story, then use this keyword.
Idol Project is a story about the pop business,
Aquarian Age is a story about a rock band,
Rahxephon is about using music to 'retune the world' - they all belong into this category.
