Variation: A A' A''
or
Ternary: A B A'
Theme (D-major)
Constrasting 2nd Part (B-minor)
Theme Variation 1 (B-flat major)
Theme Variation 2
Notes
Have to nail down the form. I like thinking of it as a hybrid: ternary and variation. As Keller always points out, Haydn was a master of variation so that whenever there is a return, a recapitualtion, a recall or rhyme, an attractive variation is axiomatic. There are a series of interesting contrasts to consider in this quartet: textural, harmonic, polyphonic, and the previously mentioned occurances of variations.
A wonderful combination of textural, rhythmic and articulation variation is established in the closed binary form of the first section.The movement opens with soft (mezza voce) violin, pizzacato accompaniment, and dainty and somewhat dry triple meter that, overtime, sounds like a charming mechanical clock. The contrasting second part, shifts to bowing (arco), legato phrases tinged with a more emphatic, singing minor key. This dicotomy characterizes the remainder of the movement.
Variation within variation. (e.g. theme in the 2nd section)
Motives: the main theme is progenitor to a number of motifs, two being most prominant. Consistent with Haydn's capable, judicious and witty handling of the learned counterpoint, you will find both motives in shifting contexts for dramatic effect: right and inverted, along with matching inversion of voice leading, first in the treble, later, in the bass. These details are intriguing, but they are not academic. They are blended within the coherent fabric of the movement so that their effect is natural, unobtrusive, intuitive.
Wonderful Haydnesque ending. A one measure sort of fantasia holds the resolution of the 3rd part (the 2nd variation) in suspension. It resumes with playful inversions, sweeps down to the tonic, and rolls on into a quaint little coda in D-major.