What is a Sonata?

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The Sonata is one of the most enduring musical forms of all time. I am not talking about the single movement Baroque sonatas of a composer like Scarlatti, but the Classical era form of Mozart, Haydn and later with Beethoven and still later the great Romantic composers like Schumann, Brahms and beyond. So what is so special about this form?

First, the sonata is a multi-movement work. I am discussing the form commonly referred to as Sonata-Allegro form which is usually the first movement of a sonata which is generally fast (Allegro). This form is not only pervasive in sonatas, but in symphonies, concertos, string quartets, piano trios, and many other musical compositions. So, what is it?

In its simplest description, it is kind of an A – B – A form, in which music is presented, new material is offered, and the original music returns. But that isn’t quite accurate. It’s more of an A – B – C form with some added structure. Here is, in a nutshell, the Sonata form:

A. Exposition

– Theme 1. in the tonic key (the key of the piece)

– Theme 2. in the dominant key (the key starting on the 5th note of the key of the piece).

– The Exposition Repeats-

B. Development: This is a free development of both themes

C. Recapitulation

– Theme 1. in the tonic key (the key of the piece)

– Theme 2. in the tonic key (so the movement ends in the key it started in!)

It is remarkable how many pieces of music adhere to this form to one extent or another. It’s not as if there was some book, “How to Write a Sonata” that everyone read! It’s just that this structure is incredibly enduring for musical exploration. It is actually the exceptions to these rules that make pieces stand out! In fact the example of the famous C major Sonata of Mozart K.545 that I utilize doesn’t follow the rules quite right. It doesn’t have the first theme in the recapitulation! It does have a statement of the first theme in the sub-dominant (the 4th note of the major key) at the end of the development and the recapitulation starts right in with the 2nd subject (second theme).

There are so many great compositions that are structured this way that you will be astounded once you start analyzing pieces you know.

Thanks for joining me, Robert@LivingPianos.com (949) 244-3729

11 thoughts on “What is a Sonata?”


  1. Interesting! I love your choice of subjects, Robert! How does a concierto differ from a sonata? Sorry,I am so dumb with the technicalities of music, but I am so-o-o-o interested in musical compositions and how they are structured! Maybe someday I will take music theory classes!

  2. Sorry Robert, but I believe you are incorrect when interpreting the Mozart K.545. It DOES have the first theme in the recapitulation! It just has a prolongation of four measures, but everything else prior to that is an exact transposition in F. The development is only 13 measures long, and ends with the reintroduction of the main theme in F.

    Also, what you are calling “Sonata” form, is more precisely called “Sonata-Allegro” form. There are other variants of Sonata form, not just this one.

    1. Brian – You really can’t call a section a recapitulation until you have returned to the original key. The original melodic material in the subdominant doesn’t count. That does make this a somewhat strange choice for the purpose, because unusual, but not “incorrect”.

      I am forwarding this link to my students because I really appreciate the tone as well as the content. Especially the last couple of minutes where Robert talks about “rules” vs. “expectations”. YES!

  3. Great discussion, Bob.

    Another way to think of sonata allegro form, is via opera:

    Two characters are introduced in the exposition, usually characters of differing, contrasting, personalities. In the development section, the two characters have a dramatic interaction, they go someplace (usually by visiting lots of new keys), and, in the recapitulation, they return, often somewhat changed by the experience. In the coda, the finishing section (which you, ahem, ignored) they provide a satisfying ending to the story.

  4. There is no rule that you cannot break to make your music more beautiful
    Ludwig Van Beethoven

    Immediately he says you have to master the rule to be able to break it. Thanks for the nice and informative video.


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