Chopin composed his most popular Nocturne when he was about twenty. A sonorous foundation for the melodic line is provided by the widely spaced notes in the accompaniment, connected by the damper pedal. The waltz-like accompaniment gently emphasizes the 12/8 meter, 12 beats to the measure subdivided into four groups of 3 beats each.
The nocturne is reflective in mood until it suddenly becomes passionate near the end. The new concluding melody begins softly but then ascends to a high register and is played forcefully in octaves, eventually reaching the loudest part of the piece, marked fortissimo. After a trill-like passage, the excitement subsides; the nocturne ends calmly.