Mozart: Piano Sonata No.16 in C major, K.545 Analysis


First Movement (Allegro)

Form: Sonata Form. C Major. 

Mozart Piano Sonata No.16 in C major, K.545 Analysis 1


Bars 1-4: First Subject in Tonic.

Bars 5-13: Transition. Some theorists consider this section to be part of the first subject, but because Bars 5-9 form an unbroken sequence that leads to dominant harmony, many consider it as being a transition in nature.

Bars 14-26: Second Subject in G major (Dominant). The remark made in an earlier sonata that it is unusual for a second subject to consist of one section only, does not, of course, refer to movements of a short, simple description such as this. Not that Bars 18-21 form a descending tonal sequence.

Bars 26-28: Codetta. These bars are usually considered to form a codetta. However, in some analyses of the movement, the second subject is marked as continuing to the double bar.

Double bar and repeat.


Bars 29-41: The short development is worked on the figures from the codetta, alternating with ascending and descending scale passages founded on those heard in the transition. It starts with a repetition of the codetta figures, here transposed from G major to G minor and, after modulating to the keys of D minor, A minor, C major and again to A minor, ends on the dominant seventh in F major, the key of the subdominant, in which very unusual key the recapitulation of the first subject takes place.


Bars 42-45: First Subject in F major (Subdominant). The re-introduction of the fist subject in the above unusual key renders this sonata specially notable, as few examples of the device are to be met with. The origin of this device is attributed to the desire that the relationship between the keys of the two subjects in the recapitulation, should correspond to the relationship existing between their original keys in the exposition. (In both parts the key of the second subject is a fifth higher than that of the first subject.)

Bars 46-58: Transition. The transition reappears lengthened, the whole of the first phrase being repeated, with the parts inverted, and this time modulating to C major (the tonic).

Bars 89-71: Second Subject in Tonic. The second subject reappears in the key of the tonic.

Bars 71-73: Codetta.

Double bar and repeat.

Second Movement (Andante)

Form: Rondo Form. G Major. 

Mozart Piano Sonata No.16 in C major, K.545 Analysis 2


Bars 1-18: Part i: Sixteen-bar sentence in Tonic.

  • 8 bars ending on half cadence (Bars 1-8).
  • Variation of the above 8 bars, ending on a full cadence (Bars 9-16).

Double bar and repeat.

Bars 17-24: Eight-bar Sentence in D major (Dominant). This new theme is founded on Part i. The sequence in the melody, Bars 17-20, and in both parts, Bars 21-22, should be noted.

Bars 25-32: Repetition of second eight bars in Part i, in Tonic.

Double bar and repeat.


Episode. This episode contains no new theme, but is founded entirely on those in Part I, to the sweet tenderness of which an indescribable pathos is added by the modulation from the major, to the minor, mode, in which of this section is written.

Bars 33-40: Eight-bar Sentence in G minor and B flat major. Starting in the tonic minor, the episode modulates in Bar 37, to B flat major, and in Bar 41, to C minor, after which a return is made to its original key of G minor

Bars 41-48: Eight-bar Sentence in C minor and G minor. 


Bars 49-64: Repetition of first sentence of Part I. Only the first sentence of Part I is repeated.

Bars 64-74: Coda. There is a transient modulation to the key of the subdominant, in Bars 65-66, repeated in Bars 69-70. The second chord, in Bar 70, is taken as an inversion of the supertonic minor ninth in this key, but quitted as an inversion of the dominant minor ninth in G major. The third chord forms that of the diminished seventh on the raised fourth in the latter key, and resolves on to the second inversion of the tonic triad.

Third Movement (Allegretto)

Form: Rondo Form. C major. 

Mozart Piano Sonata No.16 in C major, K.545 Analysis 3


Bars 1-8: Principle Subject (first entry). The principle subject is an eight-bar sentence of very regular construction, consisting of two four-bar sections. The second phrase is a variation of the first, modified to close on a full, instead of on a half, cadence. The rhythm of the entire movement is, in fact, unusually regular for, with the exception of the very last phrase, which extended to five bars, four-bar rhythm continues unbroken throughout.

Double bar and repeat.

Bars 8-16: Episode I, in G major (Dominant). The first episode is very short, consisting of one eight-bar sentence. It is founded on the principle subject, its second phrase starting with the opening section of that subject transposed into the key of the dominant.

Bars 16-20: Link. The short link starts on the chord of G, which changes, in Bar 18, to the chord of the dominant seventh in G major, and leads to the second entry of the principle subject.

Bars 20-28: Principle Subject (second entry). 


Bars 28-48: Episode II, in A minor (Relative minor). The second (and longer) episode is founded on the principle subject. It is written in the relative minor key and starts with the opening section of that subject inverted, and accompanied in the treble by a new semiquaver (sixteenth note), figure. Bars 30-32 repeat the foregoing section with the parts re-inverted. The succeeding phrase ends on a half-cadence, in Bar 36, the cadence being repeated and prolonged to Bar 40, after which the whole of the foregoing portion of the episode is repeated in modified form – the first four bars having the parts inverted. It closes finally on a full cadence in A minor. The following chords should be noted:

  • The chord of the Neapolitan sixth in A minor, both in Bars 33 and 47. In the former case, however, the chord is quitted as the first inversion of the chord of the submediant in D minor, through which key there is a transient modulation.
  • The chord of the augmented sixth in A minor, in the half-cadence, Bars 35-36.

Bars 48-51: Link. The short link ends on the dominant seventh in C major, and leads to the third entry of the principle subject.


Bars 52-60: Principle Subject (third entry).

Bars 60-73: Coda. The coda is founded on a combination of semiquaver (sixteenth note) figures taken from the second link, and the first episode.