Duex nocturnes op. 37

These two nocturnes were composed between 1838 and 1839, with first editions published in Paris (Troupenas, 1840), Leipzig (Breitkopf und Härtel, 1840), and London (Wessel, 1840). No dedicatee is mentioned. It is believed that these two pieces were composed around the time of Chopin's sea voyage to Mallorca with George Sand, a popular female writer at the time and his lover. Although the connection between this experience and the present work is uncertain, the second nocturne features a barcarolle-like section.

No. 1 in G minor

This nocturne also consists of a three-part form (A, B, A') delineated by double bar lines.

Over a left-hand accompaniment figure that consistently progresses with a slow, march-like rhythm, a melancholic theme (mm. 1-8) is played in the right hand, adorned with ornamentation reminiscent of the vocal bel canto style. This theme appears three times in section A, with appoggiaturas and fioriture added in each repetition (e.g., mm. 18, 19, and m. 36), and dynamic changes applied (1st time p-f, 2nd time f-ff, 3rd time p). Here, Chopin's melodic writing, which consciously avoided "tautology" (repetition of the same phrase) since his early nocturnes, is clearly evident. Of note in section A is the fingering 3-3-3-3 found in measure 6. While it is not common to use the same finger consecutively for multiple successive notes, here it suggests that each note of the triplet and quarter note is highlighted in a somewhat rougher rather than homogeneous manner.

In section B, in E-flat major, a warm and richly resonant four-part chorale is played consistently throughout. The introduction of a chorale into a nocturne is already seen in No. 6 (1833), providing a strong contrast to the melodic A section and further enhancing the religious solemnity. In the latter half, striking fermatas are inserted four times, foreshadowing the conclusion of the chorale.

In this nocturne, A', where the theme reappears, shows little change except for a significant reduction in length compared to A. The coda of the piece concludes with a G major tonic chord, following a plagal cadence on the IV chord (C-E-G) in G major, the parallel major of G minor. It is typical for Chopin's nocturnes to employ a Picardy third, a plagal cadence, or both, in this manner.