Structure

The piece is in F major and is in ternary form.

• A Section:

• a (measures 1-4)
• b (measures 5-12)
• a1 (measures 13-16)

• B Section:

• c (measures 17-24)
• c1 (measures 25-32)

• A Section (Recapitulation):

• a (measures 33-36)
• b (measures 37-44)
• a1 (measures 45-48)

Analysis

Sections 'a' and 'b' differ in length; while sections are typically evenly distributed, this uneven sectional structure evokes the improvisational aspect suggested by the work's title.

The theme begins with a bright, dotted, ascending arpeggiated line in F major. However, from measure 5, it abruptly descends and develops in D minor. Such sudden changes are characteristic of an impromptu. From measure 13, the theme is re-established in the tonic key.

Section B develops again in D minor. The repetitive eighth-note movement in the left hand creates an unsettling atmosphere. From measure 28, a dominant seventh chord of the tonic F major is introduced, forming a half cadence.

From the anacrusis of measure 32, the A section is recapitulated, leading to the conclusion.