(First Movement) B-flat major, 4/4 time, Sonata form

Exposition

The principal theme consists of a light-hearted, ascending staccato motif and a legato, descending stepwise motif. After a transition reminiscent of a reduction from a string ensemble, featuring a bass ostinato, chordal tremolos, leaping legato double thirds in the upper voices, and scales or repeated second intervals in the lower voices, the secondary theme appears in F major (from bar 31).

The secondary theme features double thirds spanning two octaves, with an accent placed on the third beat. Following transitional passages with arpeggiated figures and octave tremolo technique, the codetta presents a resolute four-octave unison ascending and descending stepwise passage, after which the principal theme's motif briefly reappears.

Development + Recapitulation

The movement develops through alternating appearances of the principal theme's motif and the unison motif from the codetta. The principal theme's motif dissolves into arpeggiated figures, and a scale passage, seemingly developed from the codetta's unison motif, leads to the recapitulation.

In the recapitulation, both the principal theme and the secondary theme appear in the tonic key (B-flat major), and the coda directly concludes the movement without expansion.