The sonata form consists of 3 main parts: Exposition, Development, and Recapitulation.
I. Exposition (in the major key)
1. Choose a key and create the main theme of the energetic character. This will be the so called "question" (4 measures). Tip: end on the Dominant chord.
2. An answer to the question (4 m). Tip: end on the tonic chord.
3. Repeat the question (4 m).
4. A different conclusion (4 m) in the tonic key.
5. A bridge from the main key to the Dominant. End on the Dominant of the new key (8 m).
6. The secondary theme in a lyrical character in the key of the Dominant (4 m)
7. An answer to the secondary theme (4 m).
8. A contrasting episode (question) (Dominant of the Dominant, 4 m)
9. Answer of the contrasting episode (Dominant of the dominant, 4 m)
10. Repeat of the secondary theme (4 m)
11. A different answer to the secondary theme (4 m)
12. Closing theme of a lively character in the Dominant key (4 m)
13. Answer to this theme (4 m)
14. Repeat of the answer (4 m)
15. Repeat of the second half of the answer (2 m)
16. Repeat the cadence only (1 m) in the Dominant.
17. (Optional) Repeat the Exposition from the very beginning until this place.
Tips for creating a Development section:
1. You can start with the main theme in the minor dominant key or minor Tonic.
2. When developing a theme, choose a fragment of it (1-2 measures) and use sequences, modulations, and imitations. You can also change melodic intervals in the theme, rhythms, harmony, and texture.
3. Structure you development so that 1) you will develop the main theme in the above ways, 2) develop the secondary theme, and 3) prepare for the recapitulation.
4. The preparation is usually done by using a Dominant pedal point - an episode which increases tension. Here the main emphasis is on the Dominant chord which alternates with the 2nd inversion tonic chord and/or diminished 7th chord built on the 7th scale degree of the Dominant. The reason for a rising tension is this - there is no real resolution to the tonic chord.
1. Repeat steps 1-5 from the Exposition but instead of modulating in the Bridge, stay in the tonic key. Tip: In order to end this Bridge on the Dominant chord of the tonic key, START the bridge in the Subdominant key.
2. Repeat steps 6-16 from the Exposition transposed to the Tonic key.
Variation: you can reverse the order of the main and the secondary themes in the Recapitulation.
Use these tips when composing or improvising a classical sonata on the organ. For best results, don't forget to analyze the works of your favorite composers. If you choose an opening minor key, the first modulation of the Exposition is in the relative major key. In such case, the secondary theme and later parts of the Recapitulation can be in a major tonic.
By the way, do you want to learn to improvise in the style of Bach? If so, I suggest you check out my 9 day mini course in Keyboard Prelude Improvisation.
Or if you want to learn my special powerful techniques which help me to master any piece of organ music up to 10 times faster? If so, download my video Organ Practice Guide.