The first movement is written in sonata form, as is customary. From the first theme, which recalls J.S. Bach's Invention No. 2, a motif of three initial embroidery notes and a stepwise motif connecting the 2nd to 5th notes are used throughout the entire movement (to avoid complexity, only the figures, including inversions, are shown in the explanations for each movement). Furthermore, the rhythmic motif from the second measure plays an important role in the first movement.

• Beginning
• Measures 15–18

The second theme is presented in the tonic key of C minor, just like the first theme, and the motifs of the first theme are subtly yet tightly interwoven.

• Second Theme (Measures 59–62)

In sonata form, it is customary for the second theme in a minor key to appear in the relative major in the exposition and in the tonic or parallel major in the recapitulation; therefore, this key relationship can be considered unusual. In the recapitulation, also unusually, the first theme is restated from measure 179 in B-flat minor, and after a transitional passage with repeated modulations from B-flat minor to G minor to C minor, it proceeds to the second theme from measure 219. Consequently, these 41 measures could be interpreted as a continuation of the development section. The second theme is recapitulated in the tonic key of C minor, as in the exposition, and the closing section is expanded compared to the exposition.