Nocturne cis-moll Op.posth.

A work completed in Vienna in 1830 and sent to Chopin's sister, Ludwika. It is conventionally counted as one of the nocturnes because it was listed as 'Lento in the style of a nocturne' in Ludwika's catalog of Chopin's unpublished works. It is presumed that Chopin himself did not name it a nocturne. For this reason, the tempo marking 'Lento con gran espressione' is often used as its title. The manuscript sent to Ludwika was later copied by Oskar Kolberg, a friend of Chopin's father, and an ethnographer and musician, and the first edition was published in 1875 based on this copy.

The piece, broadly speaking, follows an introduction-A-B-A'-coda structure. In the initial A section, the highly lyrical melody is striking, but the range between the lowest and highest notes of the melody spans three octaves and a semitone, making it impossible to sing in practice. Furthermore, chromatic harmony is subtly employed at the end of A, lending a delicate nuance.

The subsequent B section is divided into a first half, which continues with the same accompaniment pattern as A, and a second half, where the time signature changes to 3/4. Motifs from Chopin's own Piano Concerto No. 2 and his song 'The Maiden's Wish' are quoted.

Musical Example 1: Measures 23-24

Musical Example 2: Piano Concerto No. 2, 1st movement, Measures 41-42

Musical Example 3: Measures 21-23

Musical Example 4: Piano Concerto No. 2, 3rd movement, beginning

In the first half of this section, Chopin initially wrote the right hand in 3/4 time for two measures against one measure of 4/4 time in the left hand. However, perhaps deeming it too difficult, the manuscript sent to Ludwika features a simplified rhythm where both hands can be played in 2/2 time (Musical Example 3; this simplified version is usually performed, though some interpret this as Chopin's compromise and perform the original complex version).

Returning to A' and entering measure 53, just as the music seems to settle with a half cadence on V, the melody abruptly ascends, heightening the tension. When the bass descends to F## in the next measure, forming a diminished seventh chord, the tension reaches its peak. Between F# (the last note of the melody in measure 53) and F## (the first note of the left hand in measure 54), a cross-relation occurs, which is generally avoided in harmony (Musical Example 5).

Musical Example 5: Measures 50-52

Then, as the melody continues its descent and settles on the tonic (I), the accompaniment endlessly repeats two types of chords: the tonic and its neighboring chord. The right hand, as if muttering the same thing repeatedly, ascends and descends the scale four times, finally concluding with a Picardy third, suddenly shifting to the parallel major.