This D minor effort is one of Scarlatti's finest Sonatas and also one of his most unusual: it is really a toccata whose focus on repeated notes is said to be an attempt to imitate the sonorities of a mandolin. In addition, it makes considerable demands on the soloist with hand-crossings and other keyboard acrobatics executed at rapid tempos.
Marked Allegro, the work's opening is striking: the sound world of a mandolin is immediately invoked in the manic character of the repeated notes. Some listeners may identify this rapid-fire, tremolo-like effect more with the guitar, another instrument Scarlatti often imitated in his keyboard works.
The main theme scurries about playfully, but with a sense of urgency in its hyperactivity. The material of the second subject is just as driven, but focuses less on repeated notes, more on heightening the sense of conflict and resolution, but always with elegance, if a breathless elegance. Midway through Scarlatti turns to development of his thematic material, as was his usual course. Here the music maintains the same busy mood in expanding largely on the secondary material, and in those nervous repeated notes as well. Without a doubt this three-and-a-half minute gem is one of Scarlatti's finest and most challenging sonatas.