Cadences
The musical punctuation that ends a phrase — four types, and how to tell them apart by ear and by eye.
Explainer
A cadence is the two-chord "landing" at the end of a musical phrase — the musical equivalent of punctuation.
Perfect cadence (V-I) is the strongest "full stop". Plagal cadence (IV-I) is the gentle "Amen" ending. Imperfect cadence (ends on V) sounds unfinished, like a comma. Interrupted cadence (V-vi) sets up the expected perfect ending, then surprises you.
To identify a cadence: find where the phrase ends, name the last two chords by their bass notes, then match the pair against the four types.
Composers choose a cadence deliberately — a perfect cadence usually ends a piece; an imperfect cadence keeps a question open mid-phrase.
Worked examples
Perfect cadence (V-I)
The strongest "the end" sound — a full stop.
Plagal cadence (IV-I)
The gentle "A-men" ending heard in many hymns.
Imperfect cadence (ends on V)
Sounds unfinished — a comma, not a full stop.
Interrupted cadence (V-vi)
Sets up the perfect ending... then surprises you by landing on vi instead.