Thanks to the covid, I have to take over some music teaching from my son's piano teacher. He's preparing a swing piece for ABRSM Grade 1, and plays each 2 quavers in 'shuffle' style 2/12+1/12 instead of 1/8+1/8. I like the way it sounds, but I'm concerned that the examiners may not agree. Does that extra note in brackets after the tempo have anything to do with this?
plays each 2 quavers in 'shuffle' style 2/12+1/12 instead of 1/8+1/8
That's exactly what he is supposed to do! When you see this
at the start of a piece, you are basically told not to play straight eighths, but shuffle eighths (triplets like they are shown above -- that would be 2/12 and 1/12 like you said, although I've never heard anyone call them that).
I don't see why the examiners wouldn't agree with that. The tempo marking you've provided explicitly asks for this kind of rhythm.
There's SO much irritating about that tempo indication! All it needed was 'Swing q=120', or maybe 'swing 8s q=120'. What does 'c.120' mean? Indecision - 'pick a tempo somewhere round 120'? Fluctuation - 'play rubato centered on 120'? FFS just say 'q=120'. It's not as if the police are standing there with a metronome, we're going to play it how we want anyway! (Unless there's a click track involved, but ABRSM hasn't got into this reality of modern music-making yet.) Then there's that horrible 'Metric Modulation' notation. No, Swing isn't triplets. Just say 'Swing'.
But the intention, if not the instruction, is clear. Play 'em swung.