Every phrase needs a way to end — or to pretend it won't.
The Progression
Cadences are the punctuation marks of harmony — the short chord motions that close a musical phrase, telling the ear whether the thought is finished, paused, or deliberately left hanging. Four types cover most of the vocabulary. The authentic cadence, V–I, is the period at the end of the sentence: the dominant's leading tone resolves decisively home. The plagal cadence, IV–I, is the softer "amen," arriving without that leading-tone urgency and lending a settled, churchly close.
The other two play with expectation. The deceptive cadence, V–vi, sets up the ear for a resolution to the tonic and then swerves to the relative minor instead, prolonging the phrase and coloring it with surprise. The half cadence ends on the V itself — a comma rather than a period — leaving the phrase open and demanding continuation. Together these gestures let a composer shape momentum, breath, and closure across an entire piece.
Structure
| Attribute | Value |
|---|---|
| Authentic | V – I — full stop, decisive resolution |
| Plagal | IV – I — the "amen," gentle close |
| Deceptive | V – vi — surprise swerve to relative minor |
| Half | x – V — an open comma, ends on the dominant |
| Chords used | Major Triad, Minor Triad, Dominant Seventh |
In Practice
Cadences underlie every genre because every phrase must end somehow — the authentic cadence closes hymns, symphonies, and pop choruses alike; the plagal seals off gospel and folk; the deceptive delays the ending of ballads to heighten a final resolution; and the half cadence keeps blues and verse forms turning. They are the microscopic version of the same resolving logic that drives the ii-V-I and the Twelve-Bar Blues.