In this piece, I extensively and expansively employ "Kushi-zashi Waon" (Skewered Chords), a compositional method I have consciously used since around 2004. Variations unfold with six "11th chords" constantly "skewered" by the note C.

"Tenkūritsu" (Sky Factor) is an architectural term referring to "the solid angle projection ratio occupied by the sky" (i.e., how much of the sky is visible from a certain point). I was drawn to its romantic sound and chose it as the title. I composed this piece with the intention of exploring how the musical sky appears from the "Kushi-zashi Waon" system, and how its shape and coloration change.