A friend asked later what was the point of it – why have such a mess of arms at the piano when it would have been so much simpler with 2 pianos. Ah, but then the whole point of writing music for people in such close proximity would have been missed – it’s all about the opportunity to sit, in public, close to someone of the opposite sex and all for the reason of music.
Compare, for example, this work by W.F.E. Bach for 1 piano six hands as performed by 3 women
Social interaction, particularly under the eye of a watchful guardian, could be difficult in the 18th and 19th century. Hence all the opportunities people took to get close: let’s read together – even with the help of a candle, it provided a chance to get even closer.
And then, if you were in the parlour, some duets perhaps with flute and piano would be in order. This provided ample time for secret conversations as you discussed the music, the chance to look deep into his eyes as you started the piece together and confirmed each other’s readiness at cadences, and so forth.
Perhaps this is more about why music matters in social discourse, but we’d rather think of it as the effect of music making on the love life of our ancestors.
How many people can you fit at a piano?
Here’s 4
With 5 players, 10 hands and 1 piano, everyone gets an octave