Wolfgang Amadeus Mozart's Piano Sonata No. 1 in C major, K 279 (189d) (1774) is a sonata in three movements. It was composed when Mozart was only 18 years old.
The opening Allegro features smooth thematic material, sometimes based on sharp dynamic contrasts, with a short development (only eighteen bars long). The development sections of the remaining two movements are much more substantial. The Andante is full of expressive shading, in large measure the result of Mozart’s harmonic freedom. Some of that same freedom characterizes the concluding Allegro, which zips along in its 2/4 meter. This features an unusually active part for the left hand, another extended development section, and a surprising close: Mozart rounds the sonata off with two firm chords, which he marks Coda.
A typical performance takes about 14 minutes.
The work was written down, except for the first part of the opening movement, during the visit Mozart paid to Munich for the production of La finta giardiniera from late 1774 to the beginning of the following March.