A sound collection centered around Celtic flutes (tin whistle, low whistle, Irish flute). A boundless blue world.The concept was one I'd been nurturing for a long time. The title came first. The word ''blue'' is also part of the name of the town where I grew up, carrying many personal sentiments.After distributing the album at Summer Comiket, I completely reworked all the tracks for the M3 event, replacing it with a revised edition. The crying logo at the start of the PV is my way of saying, ''Sorry about that.'' Sorry... By the way, the sky photo used in the PV and back jacket(CD ver.) was taken above the Atlantic Ocean at the Cliffs of Moher in Ireland-a single contrail stretching among countless others.