As Easy As ABA: Understanding Sonata Allegro Form

When the average classical-music listener who has had a basic high school or undergraduate college level music appreciation course hears the term “sonata allegro form” or “sonata form,” what comes to that person’s mind — and what he or she most likely has been taught — is the architectural structure that characterizes the first movement of a typical multi-movement Classical-era or Romantic-era symphony. The reason why this form is sometimes called sonata allegro form rather than just sonata form is that allegro is often the tempo of a Classical or Romantic symphony’s first movement. But both names are acceptable and refer to the same thing.

Incidentally, there is another meaning of the word “sonata” (from sonare, which means “to sound”). A sonata is a work for solo instrument(s) in three or four contrasting movements, the first movement of which is generally in sonata allegro form. In fact, a symphony may be thought of as a sonata for orchestra, and a string quartet may similarly be thought of as a sonata for two violins, viola, and cello.

In the larger perspective, sonata allegro form (or sonata form) is a large ABA form, arguably the most aesthetically satisfying form of all because of its judicious balance of elements of unity (by virtue of the re-statement of the first A section), and variety (because the B section offers something musically new.)



The first A section of sonata allegro form is referred to by musicologists as the exposition section, because it states — or “exposes” — the thematic material.

The B section is called the development section, because it manipulates — or “develops” — the musical materials of the exposition.

The second A section, or recapitulation section, is essentially a restatement of the first A, or exposition section. You’ve surely heard sports announcers at the end of a game say “Let’s recap the game,” meaning that he or she will review the highlights of the game for you. Well, that’s basically what a sonata form recapitulation does: it tells you again what happened in the exposition, but usually with minor modifications, such as changing the key in which of one or more of its themes previously appeared.


Symphony Number 40 in G Minor, by Wolfgang Amadeus Mozart

A musical work that music appreciation college professors love to analyze for their students because it so closely adheres to the textbook model of sonata form is the first movement of Mozart’s Symphony Number 40 in G Minor. It would be ideal for the reader to listen to a recording of this movement while following the thumbnail analysis that follows:



  1. First Theme — establishes the home key of G minor.

Allegro molto


  1. Transitional music, which has a somewhat unstable feeling compared to either the first or second theme and ends with a cadence (resting point) that marks the start of a new theme in a new key.
  2. Second (Contrasting) Theme (in this work preceded by a full measure of silence) — in Bb major (the relative major key of the home key of G minor.)


  1. Transitional music.
  2. Closing Theme (Codetta) — in Bb major — whose most prominent feature is a rhythmic augmentation of the first two notes of the opening motive of the first theme, brings the exposition to a close.



In this particular work, as was often customary, the entire exposition is then repeated, helping the audience to become more familiar with the thematic and transitional material, and to better remember it. When orchestra conductors observe this repeat, the form of the movement may then be said to be AABA rather than ABA.



The development section is usually the most dramatic portion of a sonata form movement. It is here that the composer gives free rein to his or her imagination, modulates (shifts keys) frequently, but always with the expectation of an eventual return to the home key. In general, the composer here creates a heightened sense of restlessness and drama, continuous motion, intensification (often created by certain amounts of polyphonic texture), and a feeling of forward momentum — the feeling that something is always in the process of happening. Among the many important ways in which composers are able to achieve this dynamic is by avoiding settling into the home key at any point in the development section.

In the first movement of this Mozart symphony, the composer develops the following three-note melodic and rhythmic motive of the first theme only:





The recapitulation is designed to resolve the tensions of the earlier sections of the work, especially through the stability of the home key.

  1. First Theme — in the home key of G minor.
  2. Transitional music (expanded and modified somewhat from the way it appeared in the Exposition; and designed to lead back to the home key.)
  3. Second Theme — in the home key of G minor (instead of in the relative major key of Bb in which this theme appeared in the Exposition.)
  4. Transitional music (expanded and modified somewhat from the way it appeared in the Exposition, again designed to lead back to the home key.)
  5. Closing theme — in the home key of G minor (instead of in the relative major key of Bb in which this theme appeared in the Exposition.)

CODA (brief in this composition) — A coda is an added section of a musical composition, designed to bring the movement (or an entire work) to a satisfying ending.

In conclusion, sonata form is essentially a three-part form that, as Leonard Bernstein said in his Young People’s Concerts television program on this subject, creates “the feeling of balance we get from two similar sections situated on either side of the central [contrasting] development section, just as the ears are situated in a balancing position to the nose. There are two main secrets to the sonata: balance and contrast. And this idea of contrast is just as important as the other idea of balance; it’s what gives the sonata form its drama and excitement.”

Lee Evans, Ed.D., is a professor of music at NYC's Pace University. His most recent publications, for the moment available only in iPad-specific interactive digital format on SuperScore Music App, in the SuperScore folder labelled Piano Plus, Lee Evans's publishing name, are Jazz Baroque: Vivaldi/Bach (intermediate/upper intermediate level) and A Razzle Dazzle Christmas (5-finger level). Several of Evans's intermediate level popular solo piano print books for Hal Leonard Corp, include Crash Course in Chords, Jazz Piano Scales and Exercises, Famous Latin Hits 2nd Edition, Classics With A Touch Of Jazz, Opera With A Touch Of Jazz, Charlie Brown's Greatest Hits, Jazz Up Your Christmas, Lee Evans Arranges Holiday Jazz, and Starter Classics (Stipes Publishing). For additional information, visit


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