Mozart: Piano Sonata No.18 in D major, K.576 Analysis


First Movement (Allegro)

Form: Sonata Form. Bb Major. 

Mozart Piano Sonata No.18 in D major, K.576 Analysis 1


Bars 1-16: First Subject in Tonic. The first subject consists of an eight-bar sentence with full close in the tonic, the sentence being then repeated varied. It is divided into two four-bar phrases, each of which as clearly subdivides into two two-bar sections. The second phrase starts in sequence to the first on the chord of E minor, to which key there is transient modulation.

Bars 16-27: Transition. The transition is worked on semiquaver (sixteenth note) figures derived from the first subject. The greater portion of the passage is in the key of the tonic, but it modulates to that of the dominant, in Bar 25. A comparison of the opening portion of the exposition with the corresponding portion in the recapitulation shows that the phrase (starting in Bar 8), which commences the repetition of the first subject, forms, in the recapitulation, the first phrase of the transition.

Bars 27-53: Second Subject in A major (Dominant). The first section of the second subject (Bar 27-41) is founded on the first subject, commencing with a reproduction of the opening motive of the latter, transposed into the key of the dominant. The conditions, however, under which the motive is now reproduced, renders the passage very fresh and interesting. It is written with close canonic imitations, 2 in 1, between the parts, the lower part imitating the upper in the octave below, at only one quaver’s (eight note’s) distance. The second section (Bars 41-53) consists of a melody of twelve bars, containing three phrases of unequal length, viz., of four, five, and three bars respectively. The second phrase is a modified repetition of the first.

Bars 53-58: Codetta. The short codetta is founded on previous figures.

Double bar and repeat.


Bars 59-98: The section is worked chiefly on figures from the first subject and the last two bars of the codetta. It is notable for the different interesting passages of canonical imitation, variations of the passage with which the second subject opens. In Bars 63-67, the bass imitates the treble at the octave below, at the distance of a whole bar, whilst, from Bars 70-73, the treble imitates the bass at the octave above, at a half-bar’s distance. Again, the various instances of inversion of parts, and the double dominant pedal which, starting in Bar 92, accompanies the succeeding chromatically ascending passage, should be noted.

The development starts in the key of A minor, and passes through B flat major, G minor, A minor, B minor, F sharp major and minor, B minor, E minor, and A major, to D major. It closes with a link of descending semiquaver (sixteenth note) figures which leads to the recapitulation of the first subject.


Bars 98-106: First Subject in Tonic. Only the first eight bars of the first subject are heard here.

Bars 106-121: Transition, modified and lengthened. With the exception of the last four bars, the second transition is entirely new. The passage opens as if it were going to be a continuation of the first subject, but it alters at the close of Bar 108, where the bass starts imitating the treble at a twelfth below, and at a whole bar’s distance. Bars 109-112 are an inversion of Bars 106-109, the inversion overlapping the original passage. The last figure in the inverted passage is curtailed, and, in this form, becomes the starting-point of the succeeding passage. In this, the curtailed figure is imitated and repeated for several bars, the figures overlapping each other at every entry, and the whole passage rising sequentially, and modulating from G major, through A minor, and B minor, to the key of D major (the tonic).

Bars 121-155: Second Subject (in Tonic), second section reappears first. The recapitulation of the second section of the second subject (Bars 121-137) appears exceptionally before that of the first section (Bars 137-155), and is modified and lengthened.

Bars 155-160: Codetta. The codetta, slightly modified, reappears in the key of the tonic.


Second Movement (Adagio)

Form: Rondo Form. Eb Major. 

Mozart Piano Sonata No.18 in D major, K.576 Analysis 2

This is the third instance in his pianoforte sonatas, in which Mozart has chosen the somewhat unusual key of the dominant as the key for the slow movement. See also Sonatas VI and XVI.

PART I (Principle Theme):

Bars 1-8: Melody in A major, closing on full cadence. 

Bars 9-12: New four-bar phrase, with transient modulation to E major (Dominant).

Bars 13-16: Return to one of the phrases in first melody.

Bar 16: Link of three notes – A sharp, B, B sharp.

PART II (Episode):

Bars 17-26: Part i: Melody in F sharp minor and D major. Part i of the episode consists of a sentence of two phrases of four and six bars’ length respectively. The first phrase ends on a half-cadence in F sharp minor, formed of the chord of the augmented sixth resolving on to the dominant harmony. The second phrase, commencing like the first, modulates in the second bar to D major, in which key it ends on a full close, twice cadentially repeated.

Bars 26-31: Part ii: Passage, modulating and ending on half-cadence in F sharp minor. The first four bars form a modulating sequence. Starting in D major, this passage passes incidentally through E minor to F sharp minor, in which key the section closes on a half-cadence, Bars 30-31, followed by a link leading to Part iii of the episode.

Bars 32-41: Part iii: Repetition of Part i, modified to close on full cadence in F sharp major.

Bars 41-43: Link. The link is founded on previous scale passages, and modulates through D minor to A major, leading to the return of the principle subject.


Bars 44-59: Repetition of Part I (exact).

Bars 59-67: Coda. The coda is founded on the episode with, however, reminiscences of the principle subject in the demisemiquaver (thirty-second note) figures, Bars 61 and 64 and at the final cadence.


Third Movement (Allegretto)

Form: Ternary Form. Bb Major. 

Mozart Piano Sonata No.18 in D major, K.576 Analysis 3


Bars 1-16: First Subject in Tonic. The first subject lasts for sixteen bars, and is in four-bar rhythm. The close of the second phrase is interesting, and should be specially noted, as it implies a passing modulation to, and perfect cadence in, the key of the dominant. The chord of the seventh is, however, incomplete, the raised third, the distinctive note of the new key, being omitted. Bars 9-12 are a repetition of the first phrase, to which, however, a new accompaniment of semiquaver (sixteenth note) figures is added, which forms a counter-subject in the bass (compare with the passage, Bars 99, etc.). In the final phrase the semiquaver figures are transferred to the treble. The melodic sequence in Bars 1-4, and again between Bars 5-6, should be noted.

Bars 16-25: Transition. The transition commences on a short tonic pedal. It is a very simple passage, entirely in the key of the tonic, in which it ends on a half-cadence.

Bars 26-58: Second Subject in A major (Dominant). The first section of the second subject (Bars 26-44) is founded on the opening motive of the first subject. It commences in Bar 26, with the motive taken in the bass, accompanied in the treble by a new counter-subject. Bars 28-29, modulating to B minor, repeat Bars 26-27 sequentially, after which there is a slight development of foregoing figures until the half-cadence in A major (the augmented sixth resolving on to the dominant chord) in Bars 33-34, is reached. In the latter bar, and overlapping the foregoing phrase, an interesting passage commences. It is written over a pedal, with the motive transferred to the treble, and imitated by inverse movement in the tenor. The sequence (Bars 34-38), in which the two parts are consequently moving in contrary motion to each other, should be noted. The pedal ends in Bar 40, the section, however, continuing with an arpeggio and broken chord passage as far as the inverted cadence, Bar 44. The second section (Bars 44-50) contains nothing very definitely new. It rather gives the impression of being a development of the latter bars of the previous section. The syncopated melody, combined with the modulating sequence, Bars 46-48, through evidently founded on the descending passage in Bars 42-43, gives to it great freshness, and forms its distinctive feature. The third section (Bars 50-58), also, is founded on a descending scale passage. The second phrase is a variation of the first, closing on a full, instead of a half, cadence.

Bars 58-64: Codetta. This passage on a pedal modulates back to the key of the tonic and leads to the second entry of the first subject.


Bars 65-80: First Subject (second entry). The exceptional feature of this movement is the order of the following three passages. The second entry of the first subject occurs before the development, and the recapitulation of the second subject immediately follows. While the second subject can occur in that position occasionally (i.e. after the development), the second entry of the first subject preceding the development is very exceptional.

Bars 80-116: Section of Development. The section opens with a lengthened version of the transition, commencing in its original key, modulating, however, to the tonic minor, and thence to F major and A minor. Note that Bars 85-86 is in sequence wit Bars 84-85. Commencing in Bar 88, a new modulation sequence, with the semiquaver (sixteenth note) figures transferred to the bass, is interpolated, before the passage is brought to a conclusion with a repetition of the final bars of the original transition. These are transposed into F major, in which key the second portion of the development commences in the following bar. The sequence (Bars 88-90) is founded on the one occurring in the second section of the second subject (Bars 46-48), and passes through the keys of A major, G major, F major, and D minor to G minor. It should be noted that in each of the above changes of key, whether to the major, or to the minor, mode, the modulation is effected through an inversion of the chord of the dominant minor ninth. The second portion of the section is based on the opening motive of the movement. It starts with the first bars of the second subject (Bars 26-29) with the parts inverted, and continues with the second part of the first subject, similarly treated, the latter modulating from G minor to A minor. IN Bars 102-107, the above motive is worked with imitation between the treble and the bass at the fifth below, the entries in both voices, always overlapping the imitated part. The whole passage forms a rising sequence. In Bar 107, the figure of imitation is modified, the latter portion of it being omitted, and replaced in the following bars by a return to the bold arpeggio figure of accompaniment. The section closes with an exact reproduction of the final bars of the original transition.


Bars 117-149: Second Subject in Tonic. The recapitulation of the second subject is transposed almost literally into the key of the tonic. It divides into three section, Bars 117-135, Bars 135-141, and Bars 141-149.

Bars 149-162: Connecting passage founded on the original Codetta. This can be considered as the recapitulation of the codetta first heard in Part I.

Bars 163-189: Coda. The coda is based on the first subject.