Mozart’s Piano Sonata No. in C Major K.
How it works
This piece was written by Wolfgang Amadeus Mozart in 1788. This piece was written a few years into the Classical era, which started in 1775 and lasted until 1825. The rules of Sonata form had already been established by this time. Mozart himself described this piece simple enough for beginners, and it is sometimes known by the nickname “Sonata facile” for its simplicity compared to other piano sonatas. Mozart follows most of the classic form’s “rules,” with the exception of some minor changes.
The exposition of this piece’s first movement follows typical sonata form. It contains two groups, a transition, and a closing group. The exposition’s first theme, or Group 1, follows typical sonata form by staying in the tonic key of C Major, and is accompanied by an Alberti bass in the left hand. It is constructed from two motives that are only two measures long. Both motives have similar rhythmic patterns, but contrast in the melodic motion of the intervals. In the Transition, which begins at measure 5, the key switches to the dominant key of the tonic, G Major, which is common for the music of this time period. An interesting thing to point out is that Transition is longer than expected. Group 1 is only four measures long, while the Transition lasts for eight measures.
How it works
After the repeat of the Exposition, the Development begins. This section of Sonata form is commonly composed of previous melodic ideas from the Exposition. The development is thirteen measures long and contains three subsections. It modulates frequently, which is common in the development and most of the modulations follow the circle of fifths, but there are some that don’t. The development begins with the melody from the closing section of the exposition, altered to the parallel minor of G Major. After two measure sequences of scaler passages, the closing section comes back in D Minor. Then, six measures worth of sequences that contain modulatory ideas lead to an half cadence in F major, closing the Development and re-introducing the return of Group 1’s theme from the exposition.
The Recapitulation begins in the subdominant key of F Major. According to Charles Rosen, beginning the recapitulation of a sonata form piece in the subdominant key was “rare at the time it (meaning the piece) was written.” The return of Group 1 is followed by a repetition of four measures of the Transition. In the next four measures, the transition is inverted and the scaler passages are moved into the left hand, causing the transition in the recapitulation to be longer than the exposition’s transition by an additional four measures. The Transition is then completed by a common-chord modulation to the tonic key of C major. Group 2 and the Closing Group come back and are transferred to the tonic key, which completes the Sonata-form.