The Impromptu in F sharp major, Op 36
was composed in Nohant during the summer of 1839. It is the most challenging of the four to interpret, both musically and technically. The left hand begins with a walking accompaniment – the melody in the right hand only appearing in the seventh bar. When it does, it seems calm and secure (with a slight tinge of regret passing into A sharp minor). Along with a chordal section, it certainly doesn’t prepare us for what is to come. A dramatic change to D major brings a military-like theme which becomes quite heroic. Then two bars of swift modulation bring us to the unlikely key of F major where the initial theme makes a reappearance, but this time accompanied by triplets. Half way through that, Chopin makes a step up to the tonic key and remains there until the end. But the surprises don’t stop: a sudden flurry of demisemiquavers in the right hand (marked leggiero) is unexpected, leaving the left hand to sing in counterpoint. The chordal passage from the opening brings this imaginative piece to a close.
from notes by Angela Hewitt © 2004