listening to that over again, I'm almost wondering if it's two piano's or two people on the piano, cause it's weird, one part is going slow kind of back and forth in a rhythm and the other one is going really fast, if you listen carefully it almost sounds like it could be two piano's. I wonder if gackt and yoshiki are doing piano at the beginning here, or if yoshiki is just that good lol
listen to it again, see if you can pick up two completely different rhythms and see what you think.
you might even check it out on miyavi's website rather than the youtube video, honestly it sounds clearer on meev's site, it'll pop up as soon as you get on it in a second small window.
oh and it's definatly spelled S.K.I.N but I wonder what it stands for???