Prélude in D-flat major, op. 28 no. 15 "Raindrop": Sostenuto

The fifteenth of the twenty-four Preludes, Op. 28, mostly completed during the winter of 1838–39 that Chopin spent with George Sand at the abandoned monastery of Valldemossa on Mallorca. He was seriously ill, the weather was terrible, and the piano he had ordered from Paris was held at customs for weeks.

The repeated A-flat that runs through nearly the whole piece is the reason for the nickname. Sand's account describes Chopin composing during a storm and imagining water falling on the roof. Chopin himself did not name the prelude, and Sand also records that he rejected the suggestion that his music imitated anything — so the title is his companion's image, attached later by editors, and the set as Chopin published it has no descriptive titles at all.

On the page: the difficulty is not the notes but the repeated note, which has to stay even for four minutes while shifting from inner voice to melody and back, and while the middle section turns it into something ominous. It is longer than any other prelude in the set.