What is a Diminution (Counterpoint)?

A diminution in counterpoint is a technique in which a melodic line or theme is presented with shorter note values, usually by dividing the original note durations into smaller, faster rhythms. This creates a more active, ornamented, and rhythmically energetic version of the original melody.

For example, a fugue subject written in half notes might be restated in quarter notes or eighth notes in a later entry. The pitches remain the same, but the rhythm moves more quickly, giving the passage a sense of momentum and elaboration.

Diminution is commonly used in Baroque and classical music, particularly in fugal writing, to vary the subject, enrich the contrapuntal texture, and maintain listener interest. By accelerating the theme while preserving its melodic identity, composers can create contrast, tension, and rhythmic excitement within polyphonic compositions.