I've seen quite a few artist entries now,
that has their "full name" in the notes or biography. But should it not be a bit more organized when it comes to this? Maybe we could have yet another information caption, called "Birth name"? In case they'd ever use someones real name, that usually isn't used for the performer, this could be helpful (if you added the possibility to search for artists under their birth name too, ofcourse).
Since we seem to mostly use the "Given name" fields for "one name" artists, a simple birth name caption with possibly the romanized and given kanji could be convenient; Koji Kondo (近藤浩治). The field would however, probably not be useful if the real name is already the entry's display name.