Small Binary Form, or often just called Binary Form, is a musical form consisting of two main sections, labeled A and B, each of which is typically repeated.

This fundamental form has been used for centuries across various musical styles, from Baroque keyboard suites to Classical sonatas and Romantic character pieces.

Small Binary Form Terminology

The small binary form can be split up into two parts. Hence the name binary.

It is most frequently found as 16 measures, with both parts being 8 bar themes. Because it’s functions are not quite as distinct as the small ternary form, we just label the two parts… first part and second part.

The First Part

The first part of small binary form is normally a typical 8 bar theme, like the sentence or period. It can also end in any cadence, although half-cadences and perfect authentic cadences are the most common.

The Second Part

The second part of the small binary form is also usually a typical 8 bar theme. It can present a new musical idea, just as in the contrasting middle section of ternary form. Frequently, it keeps the melodic-motivic characteristics of the first part. This helps distinguish it from the ternary form. Which always has a contrasting middle section.

To truly distinguish itself as a binary form, it must not have the formal function of recapitulation.

The small binary satisfies this because it does not restate the basic idea in tonic. Note that this is different from keeping melodic-motivic characteristics.

Rounded Binary Form vs Small Ternary Form

You may have heard the term rounded binary form and thought that it sounds a lot like the small ternary. That’s because, it pretty much is. But the reason I like the term small ternary, is because you can easily see the recapitulation as a third part, instead of a continuation of the second part that is being repeated.

A small ternary form can also be called rounded binary form. This is because normally the exposition repeats itself, and then the contrasting middle and recapitulation repeat together.

This gives it a feel of a two part composition instead of three distinct parts:

But there is one small difference. Sometimes, the original theme is not brought back directly in the recapitulation section. This would mean that it is not accomplishing the formal function of recapitulation, which requires a restatement of the basic idea in tonic.

If you don’t bring back the recapitulation, you cannot definitively say there are three parts. Because of this, we really can’t be calling it recapitulation at all. This creates the need for a distinction.

Small Binary Form in Historical Context

Binary form has been a staple of Western classical music for centuries, with its origins tracing back to the Baroque era.

The Baroque Era (1600-1750)

During this time, binary form was often used in keyboard suites, particularly in dances such as the allemande, courante, and sarabande. Composers like J.S. Bach and G.F. Handel frequently employed binary form in their keyboard and instrumental works.

Classical era (1750-1820)

As music progressed into the Classical era, binary form continued to be used, albeit with some modifications. Composers such as Mozart and Haydn often incorporated binary form into the individual movements of their sonatas and symphonies. The form also began to evolve, with the development of rounded binary form, which features a return of the opening material in the second section.

Romantic era (1820-1900)

In the Romantic era, binary form remained a popular choice for shorter compositions, such as character pieces and dances. Composers like Chopin and Brahms used binary form in their nocturnes, waltzes, and other works, often expanding and adapting the form to suit their expressive needs.

Throughout its history, binary form has proven to be a versatile and enduring structure, capable of accommodating a wide range of musical styles and expressions. Its continued use and evolution are a testament to its significance in the Western classical music tradition.