Noctave
The piece
Mozart entered this sonata in his own catalogue of works as “a little keyboard sonata for beginners”; the nickname Sonata facile was attached to it later, by others. This first movement is sonata form in miniature: a singing theme over an Alberti bass, scales that race up and down, a second theme in G major, a short development. One feature stands out: the recapitulation starts not in C major but in F major, and only afterwards does the music find its way home.
The left hand plays slightly more than half of the notes, mostly as an Alberti bass (C, G, E, G in eighth notes). It must stay discreet and perfectly even: let the wrist rotate a little instead of striking every note from the finger. In the right hand, the scales need a smooth thumb crossing, because a misplaced accent gives away each change of position. The trills at the ends of phrases stop cleanly on the following beat. Practising hands separately fixes both mechanisms; then combine them slowly, checking that the bass stays under the tune.