Measures 13 to 25

These measures are a variation on measures 1–4, using the same chords but with much faster voice movement. This type of diminution, along with the auxiliary diminished seventh of the fifth degree in bar 16, helps to create the climax in bar 18.

The following example compares measures 1–4 and 13–16. The lines illustrate how the voice movement accelerates in measures 13–16:

The chord progressions in measures 17 to 25 are interesting.

In measures 20–21, Chopin uses a deceptive cadence (V–VI), then adds a Bb to the C major chord. This creates a C dominant seventh chord, but the Bb is used as a chromatic appoggiatura and resolves to a second degree chord.

Measure 23 uses a German augmented sixth chord with the augmented sixth in the bass. In many editions, this chord appears spelled as a dominant 7th (C - E - G - Bb), just as the chord used in measures 20 and 21.