Theme and Variations

In theme and variations, a composer presents a theme, usually a short, simple tune of eight to thirty-two bars, and then plays it again and again, changing something each time. Each repetition is a variation. The outline is easy to write:

• A – A1 – A2 – A3 – A4 …

The fun lies in how much a composer can change while you still recognize the theme underneath.

Ways to vary a theme

• Melodic decoration: extra notes fill the gaps around the theme's notes, often in faster rhythms.
• Rhythmic change: the theme in triplets, dotted rhythms, or a different meter.
• Change of mode: a major theme in minor, or the reverse. Composers sometimes label such a variation minore or maggiore.
• Harmonic change: the same melody over new chords.
• Texture and register: the tune moves to the bass, appears in counterpoint, or is split between the hands.
• Character: the theme becomes a march, a waltz, a slow lament or a fast finale.

▶Theme0:06▶Variation 1: decorated0:06▶Variation 2: in C minor0:06

Two kinds of variation form

• Sectional variations: each variation is a self-contained section, usually with the same length and phrase structure as the theme, and ends with a cadence. Most sets for piano work this way.
• Continuous variations: a short bass line or chord pattern repeats over and over while the upper parts change, without stopping between variations. A repeating bass of this kind is called a ground bass, and it underlies the Baroque passacaglia and chaconne. Pachelbel's Canon in D is built over one.

Well-known examples

• Mozart's 12 Variations on "Ah, vous dirai-je, maman," K. 265, on the tune English speakers know as "Twinkle, Twinkle, Little Star."
• Bach's Goldberg Variations: an aria followed by thirty variations.
• Beethoven's Diabelli Variations: thirty-three variations on a short waltz.
• The slow movement of Haydn's "Surprise" Symphony (No. 94).
• Elgar's Enigma Variations for orchestra.

In jazz, a performance that plays a tune's chord progression over and over while soloists improvise new melodies is a close relative of variation form.

Try it yourself

Take any simple tune you know and play it four ways: as written, decorated with passing notes, in minor, and in a new rhythm or meter. The Musical form worksheet has a theme and a sample variation to start from.