Cadences: How Phrases End in Tonal Music
Authentic, half, plagal and deceptive cadences, and the real reason a close sounds strong: what happens in the bass, the top voice and the metre.
Music has punctuation, and it is made of harmony. A phrase ends when the harmony, the bass, the metre and the melody all agree that something has finished. That agreement is a cadence, and its strength is not a matter of taste: it comes from four or five identifiable conditions, each of which can be weakened or strengthened on purpose.
The four cadences you meet first
Authentic is the arrival everybody knows: a dominant chord resolving to the tonic. When both chords are in root position and the soprano lands on the tonic, it is a perfect authentic cadence, and it is the strongest close tonal music has. Change either condition, inverting a chord or ending with scale degree 3 or 5 on top, and it becomes an imperfect authentic cadence: the same V–I, less final.
Half ends on the dominant. Nothing resolves; the phrase simply stops asking. In minor there is a distinctive version, the Phrygian half cadence, where a first-inversion subdominant moves to the dominant while the bass descends a semitone from scale degree 6 to 5. In A minor that is a D minor triad over F moving to E major, and the semitone in the bass gives the pause its characteristic colour.
Plagal is IV to I, the “Amen” motion. It confirms a key more than it closes a phrase, which is why it appears so often after an authentic cadence rather than instead of one. In minor the same motion with the lowered sixth scale degree, iv to i, is darker and equally common.
Deceptive replaces the expected tonic with another chord, usually vi, or ♭VI in minor. The dominant has done its work and the arrival is withheld. Deceptive cadences almost always extend a phrase rather than end it.
| Cadence | Formula in major | Effect |
|---|---|---|
| Perfect authentic | V(7)–I, root position, tonic in the soprano | full close, ends the phrase |
| Imperfect authentic | V–I with an inverted chord or 3/5 on top | close, weaker |
| Half | ends on V, commonly preceded by I or IV | pause, keeps the phrase open |
| Phrygian half | iv6–V in minor, bass 6 falling to 5 | pause with a semitone pull |
| Plagal | IV–I | confirmation rather than closure |
| Deceptive | V–vi | delayed arrival, phrase continues |
Here is a perfect authentic cadence, then a deceptive one, with the same dominant preparing both.
What actually makes a close strong
The chord names matter less than the conditions around them.
- The bass. A cadence needs the bass to move 5 to 1. Root-position dominant and tonic give that motion; inversions blur it.
- The top voice. The tonic in the soprano is what makes the arrival audible as an arrival rather than a continuation. A close with scale degree 3 on top sounds like an arrival facing sideways.
- The metre. A cadence that lands on a strong beat closes harder than the same chords landing off the beat, because the metric accent and the harmonic resolution agree.
- Directness. V7 to I with nothing in between presses harder than a resolution interrupted by a passing chord.
- Duration. A final chord held longer than the rhythm of the phrase establishes closure; a tonic that flashes past sounds like a passing chord.
- Preparation. A predominant in front of the dominant, especially a first-inversion ii or the cadential six-four, makes the dominant feel earned.
That last point is where the cadence connects to the rest of tonal syntax. The dominant does the closing, but the predominant does the travelling, and a phrase whose dominant arrives without preparation tends to sound abrupt. The reverse error is just as common in student writing: a heavily prepared predominant followed by a cadence so soft that the phrase does not feel finished.
The cadential six-four
A tonic triad in second inversion sitting on scale degree 5 in the bass is one of the most common things in tonal music and one of the hardest to label. Its notes belong to the tonic; its bass and its behaviour belong to the dominant.
Two analyses compete. One treats the six-four as a tonic chord with two notes held over as suspensions, which resolve into the dominant. The other treats the whole figure as an expanded dominant, with scale degree 5 in the bass and the sixth and fourth above it heard as accented dissonances. The disagreement is real and does not affect what you do with the chord: it cannot function as a point of rest, and it must resolve to V. Its practical value is that it puts dominant weight at the end of a phrase while the upper voices still sound like the tonic triad, which is why it so often carries the melody’s final descent.
Telling a cadence from a resting point
Not every pause is a cadence, and not every cadence stops the music. A useful test is to ask what the bass is doing and whether a conventional pair of chords is present. A long tonic chord in the middle of a phrase is a resting point; a dominant at the end of a phrase is a half cadence, whether or not it is followed by a bar of silence.
Phrase structure follows from this. An antecedent phrase typically ends on a half cadence and a consequent answers it with an authentic one, which is the smallest complete musical sentence the tonal repertoire uses. Phrases can also overlap, where the resolution of one phrase is the beginning of the next, and they can be extended by a deceptive cadence or by a cadential six-four that is repeated. When you analyse a longer piece, the cadences are the load-bearing walls: mark them first, and the phrase boundaries, the keys and the sections mostly fall into place. Sonata form is the clearest example, since its large sections are defined by which cadences they avoid and which they reach.
That is the smallest open-ended phrase there is: a tonic followed by a half cadence, with the bass stepping up to scale degree 5 and nothing resolving.
Where cadences are not the point
Pre-tonal music cadences by different means. In modal polyphony the arrival is made by two voices moving in contrary motion into an octave or a fifth, with the leading tone often supplied by an editorial accidental rather than by the mode. The effect is a cadence, but the mechanism is intervallic and contrapuntal rather than harmonic.
Popular and blues-based music often avoids cadential closure entirely. A twelve-bar blues turns around through the dominant and starts again rather than resolving; a modal rock progression can loop indefinitely with no chord asked to function as a dominant. In jazz, the ii–V–I does the work of a cadence, and the phrase ends where the tonic arrives, even when the tonic chord is a seventh chord that a common-practice writer would hear as unstable.
That last case is the useful warning: cadence is a behaviour, not a chord symbol. A seventh chord on the tonic can close a jazz phrase because the style treats it as home. The same chord in a Bach chorale would sound like a chord on the way somewhere else.
Practising with cadences
Take a piece of tonal repertoire and mark only the cadences, with no other analysis. Then label each one by type and ask what would have happened if the composer had chosen the other option: authentic instead of deceptive, half instead of authentic. Most of the interesting harmonic decisions in tonal music are visible from this angle, and the ear training studio lets you hear authentic, plagal and deceptive cadences back to back, which is how the difference stops being a definition and becomes a sound you recognise before you analyse it.
Questions
What is the difference between a perfect and an imperfect authentic cadence?
Both are V to I. The perfect authentic cadence uses root-position chords and puts the tonic in the soprano on the final chord. The imperfect one inverts a chord or ends with the third or fifth on top, which softens the close.
Is a half cadence really a cadence if the music does not stop?
It is, because it marks the end of a phrase. A half cadence ends on the dominant, so it sounds like a pause rather than a conclusion, which is exactly what makes it useful in the middle of a larger form.
