(Using examples from Mozart’s Sonata KV 309)

Sonata form … (sometimes also known as First-movement Form) is characterised by the following features:

1. It is divided into two distinct sections. The first section (the EXPOSITION) is usually repeated (on the linked recording this is from 0’00’ – 2’58”) . The second section (DEVELOPMENT+ RECAPITULATION) may be repeated. On the linked recording the development of from 2’59”- 3’54”; the recapitulation from3’55”- 5’34”)

2. The first or exposition section is characterized by a substantial passage to establish the tonic key (FIRST SUBJECT), a passage modulating to the dominant (V) key (or to the relative major (III) key, if the music started a minor key) known as the TRANSITION, a passage in the new key (SECOND SUBJECT) and closing with a short cadential phrase (the CODETTA), often emphasising the I and the V chords of the new (dominant) key.

Each of the two “subjects” may include more than one musical “theme” (or melodic idea). However, more than three “themes” to one “subject” is very rare. In the first subject of Mozart’s Sonata KV309 there is a fanfare-like theme, a more lyrical theme and a more powerful theme. In the second subject, both the first theme and the second theme are quite short.

3. The second section is characterized by being in two “halves”. The first – and usually shorter – “half” is known as the DEVELOPMENT. The second – and usually longer – “half” is known as the RECAPITULATION.

In the development the music usually becomes more dramatic by freely modulating (changing) through a range of new keys. The musical ideas are nearly always taken from the ideas used in the exposition. The dramatic high-point of the movement often occurs at the end of this part, when the music prepares for a return to the opening key (“tonic”) by emphasising the V7 chord again.

In the recapitulation the music of the exposition section returns, usually with the same succession of musical ideas, i.e., first subject – transition – second subject – coda. There are, however, three very important differences to the exposition:

  • the music of the second subject is presented in the original tonic (I) key – NOT in the dominant (V) or relative major (III) as before;
  •  to enable the second subject to be presented in the tonic key, the transition is altered to lead us from ( or rather, keep us in) the tonic key of the 1st subject to the tonic key for the 2nd subject!!
  • to extend the codetta of the exposition (often by alternating I and V7 chords of the tonic (I) key to produce an impressive ending to the music – the CODA.

Other changes, which reflect the way the music has evolved beforehand, may also occur a little unexpectedly. For example, if the development has used many minor keys for dramatic effect, it might be appropriate to bring back one theme in the recapitulation in the minor mode, when it had been heard in the major mode in the exposition, so as not to lose the more intense mood of the development as the music progresses to its conclusion. Which themes of the first subject come back in the recapitulation in the minor mode?

Now listen to the great Japanese pianist Mitsuko Uchida play the whole movement:


Variation form is often quite straightforward. The composer starts by presenting a musical theme – here in K309 it is a melody with a simple accompaniment. The theme may be an original theme of the composer or a “borrowed” theme such as a popular melody of the day. There then follow any number of altered “repeats” of the theme, each “repeat” adapting features of the theme to produce a VARIATION.

Some typical ways of varying a theme are:

a) MELODIC DECORATION LINK – as in K309 1st variation and 2nd variation
c) HARMONIC ELABORATION – as in K309 3rd variation

Take a simple piece which you know well and consider these categories carefully. Could you create eight variations of your own using this model?

Often the slow movements of sonatas or symphonies are in variation form. Many other slow movements show a mixture between sonata form or rondo form and variation form. In such cases the main theme is “varied” everytime it returns. If you listen to the whole of the second movement of the Sonata K309, you will notice a number of rondo-like episodes between the variations of the main theme indicated by the links above.

Listen to the whole of the second movement of Mozart’s Sonata KV309 and listen out for both the variations on the opening theme and the rondo-like episodes which come after the first and second variations. Listen, too, to how the second episode is a variation of the first one.

For variations on a familiar theme (the tune that is now the German national anthem) listen to the slow movement of Haydn’s “Emporer” string quartet.


(10-17” – end, on the linked recording of the Sonata K309  above)

Rondo form is also a much simpler concept than sonata form. It particularly exploits the fact that repetition and contrast make for a successful musical composition. The main opening theme (the “Rondo Theme”) returns periodically in the course of the movement – always in the opening (tonic) key. Between each statement of the rondo theme contrasting musical themes (“Episodes”) are heard. To strengthen the contrast, episodes are usually in a different key to the rondo theme. The structure of a typical rondo might be:

Rondo theme – Episode 1 – Rondo theme – Episode 2 – Rondo theme.

Listen to the finale of the the Sonata for Bassoon and Violoncello by Mozart to hear a clear rondo with the main theme coming 4 times with three episodes sandwiched between them. There is also a short rounding-off section at the end (a codetta ) to listen out for. Which episodes use minor keys?  Rondo theme is shortened sometimes. Is the the first, second, third or fourth time we hear it?

Many rondos have as many as 6 or 7 episodes with the main theme always recurring between them. In such cases it is not unusual for the first and last episodes to use the same music to keep the music more coherent.

When the rondo is used as a finale to a sonata or symphony it often takes on features of sonata form, too. In this case we can say that the music is in SONATA RONDO form.

As an example, note how, in the Sonata K309, Mozart broadly presents a rondo form shape:

Theme A – C major (link)
Theme B – G major  (link)
Theme A – C major(link)
Theme C – F major (link)
Themes BACoda – C major

Look and listen more carefully and you will discover many aspects of sonata form are also evident in this plan:

Like an “exposition” section of sonata form, two themes are presented in the tonic (I) and dominant (V) keys with a linking section between them (Theme A – link – Theme B above). This compares identically to the progress from the “first subject” through the “transition” to the “second subject” typical of sonata form.

Although they appear in reverse order, these two themes return at the end BOTH in the tonic (I) key of C major. The return of both themes in the tonic key is a defining feature of the “recapitulation” in sonata form.

Between the “exposition-” and “recapitualtion-like” sections their are many link sections and the music goes into minor and other keys, which are not just the tonic or dominant keys, like a “development” section would do.

Finally, the coda is an extended and more final-sounding version of some of the earlier music from the link sections, particularly the link section which came after Theme B.

Here’s Mitsuko Uchida again, putting it all together in beautiful playing: