SOUR '日々の音色 (Hibi no neiro)'

The EP of Japanese group SOUR titled Water Flavor (or is the song title SOUR WATER FLAVOR by a group named Torrent? or visa versa?) was released in June of this year. This video (okay, there really are only bits and pieces about this group or this release that I can find on the internet -- in English -- so I'm reading between the lines a little) was created for that release. Anyhow, that's not really the point. The point is, this is brilliant. Eddie (friend/colleague with Wycliffe UK) posted this to FB today and I'm quite smitten with it.

I'd like to know what the song is about -- but I will continue to enjoy this whether I know or not.