Frédéric Chopin

Impromptu is a term that has little technical or formal meaning, but it usually refers to a composition for piano (or, occasionally, another solo instrument) with an improvisational. An impromptu is often described as a work that results from sudden inspiration. Schubert composed eight impromptus in 1827. Of these, only one sounds improvisational, the others are highly organized, and one is a set of variations. Schumann's impromptus, Op. 5 and Op. 124/9, are also in the form of variations, as is a later piece by Balakirev. Like Schubert's, Chopin's four famous Impromptus are in ternary form (ABA). Similarities between the four works have led some writers to suggest that Chopin thought of the four as a "set" in which each successive impromptu is derived, in an improvisatory fashion, from the previous one.

Chopin composed the Impromptu in F sharp major, Op. 36, in 1839, not long after beginning his relationship with Aurore Dudevant (George Sand). The piece was first printed in Leipzig in 1840.

Chopin begins the Impromptu in F sharp major with a device he uses in several other works: it starts with a motive that has melodic characteristics, but eventually proves to be accompanimental. In this case, six measures of an idea occur in the left hand before another voice enters in the right, inverting the direction of the left-hand voice. What is most interesting is that the reiterated D sharp - C sharp at the end of this right-hand phrase also appears in the first two measures of the left-hand phrase. The second half of the theme is a flamboyant, six-measure phrase with a prominent dotted figure. Chopin repeats this pair of ideas, transposing the second of the two and extending it with a chordal passage that acts as a transition to the central section.

In D major, the central section employs the dotted figure from the A section in the bass to underpin a melody that gradually becomes thicker and more forceful over leaping octaves in the left hand. This dissolves quickly, heralding the return of the first theme, which begins, oddly, on F major, eventually returning to F sharp. The coda, as lengthy as the music that precedes it, begins with one of Chopin's technically dazzling passages. The extremely fast scales and turns of the right-hand line are given a simple accompaniment, allowing the listener to completely focus on the awesome technique necessary to perform the right-hand passage.