Although I can feel that 開け放つ窓 sounds pretty,although I understand Japanese,I still don't understand she wanna tell what? akehanatsu mado? why?? :/ ------ Anyway,I love this song & I've repeated it a whole day!xD
Stumbled upon Abe Fuyumi when I listen to radio, where it plays 開け放つ窓 ~piano version. I don't know who is the singer but I take one part of the lyric and search it on google and finally found her. Her voice is really nice and serene.