The piece
This nocturne rests on two clearly separate worlds. First, a G minor melody, Andante sostenuto, laden with ornaments and carried by steady left-hand chords. Then, at the centre, a chorale in E-flat major: four-voice chords moving slowly like a hymn, before the melody comes back. The score follows the first edition by Breitkopf & Härtel in Leipzig, with a few notes adapted by Noctave.
The melody has more than fifty groups of grace notes: they are inflections of the voice, not displays. Keep them light while the main note stays clearly present, and check that the left hand does not slow down to wait for them. That hand often plays the bass in octaves, more than a hundred times, followed by a chord: a round octave, a lighter chord. The chorale calls for another frame of mind: it is all about the legato of the voices and the balance of the chords, with the pedal changed at each harmony. Finally, take care over the move from the chorale back to the theme.