Sonata form is a complex manifestation of a harmonically open, rounded binary form that is also balanced.

The first reprise is called the exposition, and the second reprise contains the development and recapitulation.

The exposition has two core sections in different keys called the primary theme and secondary theme.

The primary and secondary themes are separated by a transition.

The secondary theme is typically followed by a large suffix called the closing section.

The development and recapitulation may have a retransition between them.

The recapitulation's secondary theme should be in the overall tonic key.

The sonata form proper may be preceded by an introduction or followed by a coda.

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At the largest level, the form is as follows in Example 1, and each of those large levels is further subdivided, as shown in example 2.

[](https://viva.pressbooks.pub/app/uploads/sites/12/2020/04/sonata-largest-level-2.png) Example 1. Sonata form at the largest level.

[](https://viva.pressbooks.pub/app/uploads/sites/12/2020/04/sonata-form-complete.png) Example 2. Standard formal layout of a complete sonata form.

Exposition

Due to its popularity and intricacy, sonata form has developed its own set of terms to help capture its multiple formal components, but these components share properties with other formal sections (see Formal Sections in General). The sonata form's first reprise is called the "exposition," because it exposes the main thematic material of the work. The exposition can be further broken down into four sections with specific names:

Primary Theme (P): the main section, in the tonic key; concludes with a cadence in the tonic key

Transition (TR): the connective section; concludes with the medial caesura

Secondary Theme (S): the contrasting section, in a non-tonic key (typically V for major-mode pieces and III for minor-mode pieces); concludes with the essential expositional cadence

Closing Area (C): a large suffix in the non-tonic key.

[](https://viva.pressbooks.pub/app/uploads/sites/12/2020/04/sonata-exposition.png) Example 3. Standard formal layout of a sonata exposition.

On the whole, the exposition is a relatively stable part of the form. P, S, and C are all typically very stable areas; only TR is unstable.

In the exposition, expect the secondary theme to start and end in a non-tonic key. In major-key sonatas, this tends to be the dominant (V), and in minor-key sonatas, this is usually the mediant (III) or the minor dominant (v). These keys are very common in the 18th and 19th centuries, but other options also occur in the 19th century.

Dependent and Independent Transitions

The exposition’s transition between P and S takes one of two forms, depending on whether the transition’s melodic/motivic material clearly derives from P: if it does, the transition is dependent, and if it doesn’t, the transition is independent. An independent transition is usually easier to locate because it sounds like something new instead of a continuation of P. Dependent transitions might begin like a restatement of P but veer off in another direction after getting started, and they typically build energy and feel relatively unstable. A dependent transition typically involves the process of becoming because it initially sounds like P is ongoing, but as it continues, its transitional function emerges without clear delineation between the two. Another type of dependent transition can occur when P's suffix doesn't come to a clear end and instead evolves into a transition through the process of becoming. However, becoming is such a common aspect of dependent transitions in sonata form that most analysts don't bother labeling it as such.

Development

The development is a large, unstable section. Like other unstable sections (e.g., B in rounded binary form and C in sonata rondo), the development typically favors sequential passages, chromaticism and modulation, and partial (rather than complete) thematic statements. As the name implies, the development may "develop" material from the exposition, but this is not a requirement, as the development may also introduce its own material.

Developments often explore multiple key areas through modulation or extended tonicizations. The sequential passages in developments often involve models that are quite long, often four to eight measures. For example, in the development of the first movement of Mozart's Piano Sonata in A minor, K. 310, discussed in the analysis example below, a four-measure sequential model is used. Sequences make up such a substantial portion of Classic-era sonata developments that William Caplin suggests focusing on them when determining their overall structure. He thinks of each sequential passage, from its model to its eventual half cadence, as a "core"; suggests the possibility of multiple cores (usually only two); and describes the music between the beginning of the development to the first core as the "pre-core."

Because developments explore non-tonic keys, they typically end with a retransition (either small or large) that helps to prepare the return of the primary theme in the tonic at the start of the recapitulation. The development often ends with a medial-caesura effect that marks a clear dividing line between the development and recapitulation. But this boundary can be less clear as well and even involve an elision, and in some cases, P starts over a dominant pedal, making it hard to hear as a clear point of initiation.

Recapitulation

The recapitulation involves the restatement