Part of Me?
 

This is a very stupid question, but what album/single is part of Me on? Is it only on A BEST 2 -Black-?

^yep, only on A BEST 2 -BLACK-.

It is only on A BEST 2 -Black-, yes. :yes Too bad part of Me isn't on any other album... :(

^I know! :(

imo it sounds very secretish. I think it would have done very well on there. But then again, it's an unreleased song because they needed something to promote it. a best had new vocal and mixes, a ballads had 2 new songs (rainbow, and sotsugyou), a complete had mirrorcle world, a best 2 needed something, other wise there wouldn't be anything new to promote it with and no on would really want to buy it. Having a new unreleased song, with a brand new never before seen video was the enticing news they needed to really help sell the album.