Half cadence

The open ending

A cadence is, according to the page Cadences, the harmonic punctuation of music: it closes a phrase or leaves it open. The half cadence is the open variant. It ends on the dominant, so exactly on the chord that builds up tension and presses back to the tonic. Because the resolution is withheld, the phrase stays suspended. The page describes it as a breath mark in the middle of the sentence that makes you expect an answer.

Which chords lead to it?

The half cadence is not a fixed chord formula but a goal: what matters is the last chord, the dominant. On the Cadences page IV – V, ii – V and I – V are given as common routes. In C major those would be F – G, Dm – G and C – G.

Notice how the ending stays suspended. It “wants” to go on. Then play the full close for comparison: the same chords F and G, but with the target chord C at the end.

In minor the same holds, except that for an effective ending the dominant appears as a major chord, in A minor so E major with the leading tone G♯.

Question and answer

Because the half cadence stays open, it is suited as a question that a full close answers. In songs and dances this builds up many melodies: the first phrase ends open, the second returns with an ending on the tonic. The building block Form names the period as the most important small formal unit: two phrases that behave like question and answer. This pair of antecedent and consequent is called a period; the antecedent typically ends on the dominant, the consequent closes on the tonic.

Telling it from the other endings

The half cadence is the only one of the four standard endings that does not land on a tonic or its substitute at all. The full close and plagal cadence arrive, the deceptive cadence seems to arrive, but on the wrong chord. Anyone who looks only at the last chord of a phrase can therefore tell the four apart easily: tonic means arrival, dominant means question.