This sonata is a very good model for expanding the sonata-form with various internal and external devices, such as cadenza, tonal mode-change or visiting remote keys.
The main theme is in sentence form with 4 bar extension. Transition begins in a very contrasting way in terms of dynamics and piano technique. It is double forte and consists of arpeggios and broken chords. It does not contain a thematic material. At the 21th bar, it starts to stand on V to maintain the subordinate key. Transition ends in 26th bar with medial caesura (term used by Hepokoski). As expected, subordinate theme starts in G but with a mode change from major to minor. The theme is also presented in d minor. After its presentation in both g and d minor, there comes a transition like link to reach 2. Subordinate key in G Major. The second theme progresses as a dialogue between right and left hand. After its presentation, there is an interesting point in terms of formal plan. At the 61th bar, there comes the transition of primary theme zone. It is like a some kind of intervention to the secondary theme zone but, in my opinion, the intention is to create a sort of cadencial progression or to close the subordinate theme by using the material of transition. After the PAC in 77th bar, it closes itself with a codetta.
Development starts with the material from codetta (small, short trills in both hands). The Core starts with D7/bIII and through chromatic chordal progressions, it reaches to D Major. This is where the false recap occurs. The main theme is presented in D Major. Starting from false recap, there is the repetition of a certain thematic model in c,a,f minor. In 129th bar, retransition begins which leads to the “true” recap in C Major.
Recap occurs in the way it is expected. No change in the tonal plan of recap. An expanded coda starts in 211th bar. It contains a small cadenza which is not very familiar for the sonata form. Starting from 222th bar to 232th, there is a dynamical and harmonic climax which is built on diminished seventh chords. After the small cadenza, main theme is presented again and the movement ends with broken octaves in a very majestic way.