It has a dancing character midway between waltz and mazurka, and it rises to a tremendous climax before wending its chromatic way back to the home key, introduced by a little left-hand cadenza in octaves. This Nocturne includes a contrasting middle section, a feature of many of Chopin’s essays in the form.

The melody starts on E-natural, giving us the C-sharp-minor home key, but immediately moves up a half-step, creating a chromatic yearning in the melody as well as a modulatory restlessness in the harmony – melody, harmony, and texture are inseparable in Chopin. The very beginning of the C-sharp-minor Nocturne, for example, is in harmonic no-man’s land, with no third in the arpeggio. But so too are the sublime touches of genius with which Chopin elevated the received archetype. The expected dreamy sensitivity projected by a bel canto melody over rippling broken chords is there in abundance in both works. 27 were composed in 1835 and published the following year in Leipzig, Paris, and London, dedicated to the Countess Thérèse d’Appony, in whose salon Chopin often appeared. And although they had influential predecessors – from the Irish pianist John Field, for one – and a host of imitations, it is Chopin’s nocturnes that continue to define the form.

He composed them throughout his career, they were his most popular works with his contemporaries, and most of them were published in his lifetime. The nocturne is most distinctively Chopin’s own form.

Nocturne in d flat major