Nocturne Op.55 No.1 in F Minor 夜曲 作品55之1 F小调

Composed in 1842–1844, the F minor nocturne has an average duration of about 5 minutes.

Structure
The piece is in ternary form (ABA). Its main theme has a slow 4
4 with a heavy, steady crotchet beat. It starts with the main theme which repeats once with only minor variations. The right hand plays a slow melody and the left hand accompanies with a bass note and then a chord, in crotchets. The second section is then played with, again, the right hand playing the melody and the left hand accompanying with bass notes and a chord. Although there are occasional changes to this pattern, for example the left hand plays a sustained minim with a crotchet chord above. The main theme then comes back in with some variations to the first two times it was played: a triplet phrase is added to the third bar of the section. The second section is again repeated with no variations, followed immediately by the first section again with the triplet sequence. A tempo change to più mosso speeds up the piece. It starts off with some fast, triplet quavers and then three loud (forte) chords. This then repeats three further times until a completely new section comes in with a melody in the right hand and triplet broken chords in the left (see score on left). A descending scale and some large chords completes this section and leads it onto the first theme again.

There is then a large variation on the first theme where the main tune is played with other notes in between. There is then a large section of arpeggios and finishing off on six final chords, then modulates to the parallel key of F major for an interrupted final cadence.

There are two short chorales. The first, at bars 71–72, marks the transition from B section back to A, while the second, at 98–101, concludes the piece, in F major.

The piece was described by Frederick Niecks (Chopin's biographer) as: "we will note only the flebile [feeble] dolcezza of the first and the last section, and the inferiority of the more impassioned middle section".

Op. 55, No. 1为F小调，长度约为5分钟。右手部分以4/4拍的行板弹出缓慢的旋律，左手以一个低音接著一个和弦作伴奏。开首中第一主题出现两次。然后是第二主题和加入三连音的变化的第一主题，并出现两次。之后是标注Più Mosso（稍快）的和弦乐段，旋律共出现三次。然后是全新的旋律和左手部分的分解和弦。第一主题再度出现，但被大幅修改成连续的三连音，最后以6个阔和弦作结。乐曲的终结部分由F小调转为F大调。

此曲曾于电视剧大西洋帝国中播出。电影末日戒备中一个恐怖份子头目为音乐教师，他向一名小妹妹弹奏此曲以讲述感受歌曲中细微差别的方法，后来电影更加入此曲的交响乐版本为背景音乐。