What is Sonata Form?

Sonata Form is a type of musical structure in 3 main parts (Exposition, Development, and Recapitulation), it is one of the most popular musical structures traditionally used by composers.

The first section is called the Exposition, and is where the composer introduces the main musical themes of their piece, there are generally two. The Exposition is usually split into two segments (one for each main theme) joined together by a transition section - it is common for the first section to be in the tonic key (for example C major), and the transition to lead into the second section in the dominant key (which would be G major). There can also often be a small closing section to end the Exposition segment.

The Development section is far less structured and tends to be where the composer experiments and changes the ideas they have presented in the Exposition section. Despite this lack of structure, it is common for the Development section to begin in the same key as the Exposition finished in (the dominant). Development sections are generally more erratic, and the music frequently travels through a series of keys in a short space of time.

The Recapitulation section is the final section of Sonata Form. In this section, the (generally two) themes of the Exposition return, however rather than the two themes being in different keys as in the Exposition, in the Recapitulation they are most commonly in the same, tonic, key. At the close of the Recapitulation section, there is frequently a Coda to bring the piece to a close.