Noctave
The piece
This rondo closes an unusual sonata in which no movement is in sonata form: the first is a theme with variations, the second a minuet. Mozart marked it Alla turca, and it calls up the music of the Ottoman janissary bands, with their drums and cymbals, then fashionable in Vienna. Two colours alternate: light, quick episodes in A minor, and a refrain in A major, in octaves, which keeps returning until the coda.
Nearly all the grace notes belong to the left hand: each chord is spread by three quick notes before the main note, like a cymbal stroke. Play them tightly packed, in a single wrist movement, so the chord sounds crisp rather than like a slow arpeggio. The right hand plays more than a hundred attacks in octaves, mostly in the refrain: keep the hand open and let the wrist do the work, without stiffening the forearm. In the episodes, the opening sixteenth notes (B, A, G-sharp, A) stay even and quiet, at six or seven notes per second.