If you're playing in a group in Japan and your members all happen to be female, sooner or later you're going to get slapped with the "girls' band" tag. The term has been used willy-nilly to describe everything from the manufactured guitar-pop of late-'80s chart-toppers Princess Princess to the experimental rock of Nisennenmondai.

For long-running Tokyo quartet Falsettos, it's an awkward fit. But what's the alternative?

"I saw someone on Twitter describe us as a 'moms' band'," says Miuko Nakao, the group's guitarist, singer and lyricist.