The Bemani series copytags don't get any more granular than subseries (i.e. Beatmania IIDX), but the characters have different costumes in different games, which currently is untagged whatsoever... For example, Hishimiya Tsugaru - post #6359496 is her outfit from IIDX 28 Bistrover, post #1715220 from IIDX 20 Tricoro, post #8716492 from IIDX 32 Pinky Crush, etc. The other mascot characters almost always get new costumes as well.
This is making me wonder if we should have copytags for the individual games? At least, the ones with unique costumes or other content, that is. My only concern is that it might accidentally be a can of worms in regards to Bemani as a whole, plus that would make a four layer implication :/
The can of worms thing is why I specify with unique costumes, because obviously I don't think it would be beneficial to tag like, the individual Dance Dance Revolution games. I'm not sure if other Bemani games have similar unique costumes for entries - maybe Sound Voltex and Pop'n Music?
There's also the alternative of tagging costumes as chartags, but given that a game can have new costumes for like three characters and they're not named it seems... Not ideal? We do have Kureha (666) (Sound Voltex), I suppose, but that's an appearance from a specific song, not a whole game.
Edit: Seems there's definitely more unique content than just costumes and songs to the individual games, too, post #8870259 features a character unique to Beatmania IIDX 26 Rootage, I believe?