Firstly, the earlier sonata is more intricate in its division of the 2 beats-a-bar (see excerpt 1). Incisive and vigorous the opening phrase is decorated with ornaments such as trills; the rolls of the two triads and the grace notes complicate the sound of the opening. 1. It has been remarked that this is reminiscent of Joseph Hayden's style in a set of six sonatas published a year previous to the K281. This decorative style is carried all the way through the music as seen with 18 other trills as well as a series of appoggiaturas and turns. Also the there is a huge amount of the alberti base being used- in natural fact almost 2/3 of the melody line is played over an alberti base. .
However, this influence completely disappeared by 1789 when he wrote the K570 (see excerpt 2). The opening is a unison melody played by both the left and right hand, which is highly unusual for piano works of the classical era where the left hand either filled out harmonies or began an alberti base accompaniment. There have been suggestions that this work was not intended for piano solo but instead a violin sonata, which explains the homophony of the opening arpeggio, sequence. It would be pertinent to note that his earlier work seem a great deal more ambiguous in dynamic markings than his later work. While K570 is given a piano marking from the onset of the piece but Mozart does not include similar marking for the opening of K281. Mozart's dynamics are not as diverse as those used in the romantic era by composers such as Beethoven and there are only piano and forte markings in the music. .
This similarly to the tempo allows for a certain freedom-although certainly not aleatoric or rubato. It is only after the opening sequences in K281 that the composer adds specific directions. .
In terms of structure the first movements of the two sonatas are extremely similar-appearing to follow rather strictly the sonata form.
