The video attached explores how to analyze and practice Variation 1 of Mozart’s Sonata in A, K. 331 which is distinguished by its opening movement in Theme and Variations form.
The following link provides provides exploration of the opener: https://arioso7.wordpress.com/2012/03/17/the-most-heavenly-piano-music/ Its lilting theme threads through each of 6 variants, retaining the binary form, and enlisting a particular device which should be clearly identified.
In the first variation, the composer employs many non-harmonic tones in half-step relationship to principal melodic notes, and these strike dissonances between the treble and bass.
The other prominent feature of variation 1, is the way the composer groups or phrases the notes. There are a preponderance of two 16th-note and three-16th-note groupings in alternation, which gives a cajoling character to the music. Using a rolling wrist motion to execute these figures prevents the typed-out sound.
A very tricky variation to play because of its slurred groupings, the interspersed broken octaves in the bass require finger substitutions to keep them buoyant and nicely shaped. In addition, sudden, interspersed “sfzs” (sforzandos) must retain a certain Classical era refinement and not be too obtrusively accented.
After initially practicing the variation in separate hands, slowly and without pedal, it’s a good idea to lightly add sustain in a tasteful manner giving the variation a bit of warmth.
The instruction follows: