Definition
Binary form consists of two sections, almost always repeated (AABB, written with repeat signs). It is the form of Baroque dances, of many variation themes, of minuets and Classical trios. Its engine is tonal: the first part moves away from the tonic, the second returns to it. There are several variants, distinguished by two questions: where does the first part end, and what happens at the end of the second?
Where the first part ends
- Continuous binary: section A ends in a different key (on the dominant in major pieces, on the relative major or the minor dominant in minor pieces). The music “is not finished”: it has to continue.
- Sectional binary: section A ends on the tonic, with a perfect cadence or a half cadence. Each part is more self-contained.
What happens in the second part
| Type | Structure | Characteristic |
|---|---|---|
| Simple | A ‖ B | B takes up the motifs of A, passes through other keys and closes on the tonic, without an explicit return of the beginning |
| Rounded | A ‖ B + A' | in the middle of the second part the beginning of A returns in the tonic; it is the seed of sonata form |
| Balanced | A ‖ B | the end of the first part (in the dominant) returns at the end of the second transposed to the tonic; typical of Scarlatti's sonatas |
A rounded binary is distinguished from a ternary because the return of A is tied to the second section (it is repeated with it) and is often shortened, whereas in ternary A returns as a complete and independent section.
Typical tonal scheme (in major, C)
- A: C → modulation → cadence in G.
- B: starts from G, passes through other nearby keys (A minor, D minor, F) → return to C.
- In minor (A minor): A ends in C major (relative) or in E minor; B returns to A minor.
Practical rules for analysis
- Find the repeat signs: they divide the two parts.
- Look at the cadence at the end of A: in what key? Perfect or suspended?
- Look in the second part for the return of the opening theme in the tonic (rounded) or of the cadential material of A (balanced).
- Compare the lengths: B is often longer than A, because it has to travel between keys.
Common mistakes
- Calling every rounded binary a ternary.
- Ignoring the key at the end of A: it is the most important piece of information for classifying the form.
- Thinking the two parts must be contrasting: in Baroque binary they often use the same material.
Examples
- Bach, French and English Suites: allemandes, courantes, sarabandes, and gigues are almost all continuous binaries (A ends on the dominant or the relative).
- Scarlatti, Harpsichord Sonatas: many are balanced binaries, with the final material of A taken up in the tonic at the end of B.
- Mozart, Sonata K. 331, theme of the first movement: rounded binary (the second part brings back the opening phrase).
- Haydn and Mozart minuets: almost always rounded binaries, often with a shortened return.
- “Oh! Susanna”: a folk song in rounded binary form.
How to use it in composition
- For a miniature (a dance, a video game piece, a jingle) binary is perfect: two sections of 8 bars each, with the first ending on the dominant.
- If you want an effect of return and strong closure, choose the rounded; if you want continuous flow, the simple; if you want a feeling of symmetry, the balanced.
- Rounded binary is the antechamber of sonata form: practicing with it prepares you for writing larger movements.
Exercise
- Write a minuet of 8+8 bars in F major: the first part ends in C, the second returns to F, taking up the first four bars.
- Analyze a Bach gigue: where does the first part end? Is there a return of the beginning?
- Turn the piece from exercise 1 into a balanced binary.
Connections
Binary, ternary, and AABA form; Minuet and trio; Baroque suite; Sonata form; Theme and variations; The period: antecedent and consequent.