Sostenuto in Chopin Op. 62-1

Hi Mark, I'm actually revisiting this delightful piece now to record for my dad's birthday! That's a great question - my piano coach and I discussed the sostenuto a couple of days ago. For me, part of it is feeling a longer singing line with the RH voice, and part of it is using a bit more tenuto LH articulation and pedal, as opposed to the light and lively A section where I'm really trying to lighten up the LH and pedal. Interpreting "sustained" as longer articulations and a touch slower, rather than only slowing down the tempo Even within the sostenuto section, my coach encouraged me to find variety in how I presented it, which I'm working/struggling on now. I should probably take your lead and listen to more recordings  

When I worked on this nocturne, my teacher wanted me to make the RH very sustained and legato and to bring out the LH bass notes but keep the LH chords very light. As a contrast to using rubato in other sections of 62/1, I worked on keeping a precise tempo in this section to really bring out the syncopation. This creates a rhythmic tension that is then broken in the opening of the poco piu lento section beginning in bar 68.