Sonata Form

Pretty much all symphonies and concertos from the classical period follow the same sort of structure – 3 or 4 movements, of which the first one is in Sonata Form. Since it was ‘invented’ in the 17th century, when instrumental music started to become its own separate genre from regal choral music, it has been widely used and is still popular today, although it has changed dramatically from the simple form it once was.


At a really basic level, the sonata form has three sections.

  • an Exposition – where the melodies are introduced
  • a Development – where they are developed, and
  • a Recapitulation – or recap for short, where they are repeated again.


The exposition has a few subsections as well, and the annoying thing is that not all sonatas have them. I’ve put in links to the relevant sections in this example – Haydn’s Clock Symphony, which is pretty ‘normal’. Also it’s one of my youtube score videos. #shamelessplug

  • Most sonata forms start with a slow introduction. (0:00) There’s no real rules within this, but normally it lasts a few minutes, exposing the first real melody before moving into the next bit, where things start getting interesting…
  • Next comes the first subject, (1:36) or the main melody in the sonata form. It’s usually pretty rhythmic, and often staccato, or detached in articulation. This only lasts a few bars before…
  • The Transition section (1:45), which links the first subject with the second subject. In almost all Classical symphonies, you can tell where this is because there is an orchestral tutti – basically everyone suddenly starts playing. The transition section often has a little development of the ideas from the slow introduction and first subject – this might include rhythmic diminution (speeding things up while still staying in time) or inversion and retrograde (meaning turning the melody upside down, or playing it backwards… but this is usually pretty difficult to spot and will come later on in the actual development section) More importantly, this is how the music modulates to the key of the second subject.
  • The second subject (2:38) comes next, which is where the rules start. If the piece is in a major key, the second subject is usually in the dominant key, which is a fifth higher than the tonic (starting) key. For example, if the first subject was in C major, the second would be in G major. However, if the piece is in a minor key, the second subject is in the relative major. That’s the one with the same key signature, or one minor third higher, and in the major key. Second subjects are usually more lyrical and legato.
  • Usually a codetta (somewhere around 3:00) follows, which is a fancy way of saying the music rounds off onto a cadence before the next section. Sometimes (like in the Haydn) this is sort of merged with the second subject. Sometimes old tunes come back here though, for a little bit.
  • If a piece is traditionally Classical, the exposition from the first subject onwards is repeated before the development. This is one of the rules that composers in the Romantic era decided to play around with.


There are pretty much no rules for what goes on here… but there is usually a lot of modulation, sometimes to completely unrelated keys. In Haydn 101, the development section also contains:

  • Imitation, as the melodic line jumps between 1st and 2nd violins from the 2nd time bar at 4:40
  • Passing modulations – sometimes called tonicisation – of a lot of minor keys, reaching D minor (the tonic minor) by 5:17, and a tone higher in E minor by 5:23.
  • Antiphony between sections at 5:27 – notice how the accompaniment jumps from the brass to the woodwind and back. Antiphony is a type of texture and basically means a call-and-response idea.
  • Use of pedal points, inversion, harmonic and rhythmic diminution and augmentation, all before finishing at the fermata (pause) at 6:05 before the recap.

Developments can be extremely drawn out and experimental, manipulating and reinterpreting melodic and harmonic material from the exposition, but every composer is different here, and you can often find out a lot about the composer’s style from the way they write their development section. For example, Haydn’s developments often follow a similar pattern of using a subject as a sequence, to modulate to related minor keys – if you don’t believe me, there are 103 other symphonies you can look at, and certainly his later ones that start in a major key all get to a minor key only a few bars into the development.

However, composers like Tchaikovsky would never be as traditional – less than 100 years later, in his sixth symphony, the Pathétique, he starts the development with counterpoint based on the first subject and slow introduction motif – which are both pretty much the same melody.

Mahler on the other hand would never be as predictable as Haydn, since in his first symphony, the music at the development section suddenly becomes extremely still and atmospheric, with distant birdsong in the flutes giving a programmatic feel. His second symphony’s development section of the first movement jumps straight into the first subject music again, but sped up, and in compound time, rather than simple time.


The Sonata form had just torn the exposition themes apart in the development section, so the purpose of the recapitulation is to replay them, pretty much as they orginally were, with a few small changes to close the movement in a satisfying way.

  • The first subject usually came back, and Haydn doesn’t change a thing in the Clock Symphony (6:06)
  • The transition follows, and this is where it gets interesting. Notice at 6:19 it suddenly modulates to the tonic minor – this is so that the second subject can be played in the tonic key, so we finish in the same key in which we started.
  • The second subject at 6:33 is repeated now, but with some changes. Haydn decides to mix things up by giving the melody to the ‘cellos, instead of the violins – they play a new countermelody over the top in the second bar of fig. 7. The point is that the melody is repeated in its original form, just in a new key, and in this case, with some new orchestration.
  • The codetta is a little longer here as well – and a long codetta is just a coda. This time, Haydn brings back the first subject again, rounding off the piece with a pleasing circularity to everything.

You might notice that he has left out the slow introduction – this isn’t always quite as important as the first and second subjects, so it often doesn’t make it back to the recapitulation. This time, Haydn leaves it out, but if you look at his other symphonies, like his 103rd ‘Drumroll’, the low ‘cello and double bass motif returns in the coda.

In other symphonies, like Tchaikovsky’s 5th Symphony (Links to my Tchaikovsky 5 score video), the slow introduction is much more important, since it becomes the defining melody of the entire symphony, returning in dramatic fashion in the second movement at 25:30, closing the third movement at 38:30, and opening and closing the finale movement at 39:16 and 48:45.

I hope you’ve found this article interesting 🙂 This description is my own based on my own knowledge – with a little help from wikipedia for the history of the structure – so feel free to quote and refer to it in whichever way you wish. If you disagree with anything I’ve said, or if I’ve made a factual error, please comment below and I’ll elaborate more, or sort it out. I’m not a professional, so this is by no means a perfect and exhaustive description 🙂

Please consider donating if you found this useful!