https://itunes.apple.com/jp/playlist...bf21c2fcb62df5
Looks like it's just a playlist, nothing too exciting. I'm guessing these are created to help listeners delve deeper into an artist's discography, sort of like a deep cuts best of. There's ones for other artists, too:
Daichi Miura:
https://itunes.apple.com/jp/playlist...62d6f5fc3?l=en
Utada:
https://itunes.apple.com/jp/playlist...27b052a16?l=en
Kaela Kimura:
https://itunes.apple.com/jp/playlist...314e02ca6?l=en
Björk:
https://itunes.apple.com/jp/playlist...6422598a4?l=en etc.
You get the deal.