The half cadence

A phrase may close on the dominant itself: the harmony reaches the chord of maximum tension and stops there, root position, on a strong beat, leaving the resolution owed. The half cadence is the tradition’s question mark — it divides a period into question and answer, and it works precisely because the dominant is stable enough to stand on and restless enough that no one mistakes it for the end.

Marks the midpoint of a period: the antecedent phrase asks its question here, and the consequent phrase supplies the answer later with a full cadence, so its whole identity depends on something still to come. It needs root position and a strong beat to read as a real punctuation mark rather than a passing dominant — an inverted or weak-beat dominant sounds like harmony in motion, not a stop. Because it withholds resolution rather than avoiding it, it closes a phrase with real finality while leaving the tonal question wide open.

• Sounding the dominant in an inversion, which lets the harmony pass through rather than stop, when the device depends on root position to read as an arrival.
• Landing the dominant on a weak beat, so the ear hears it as transitional rather than as the phrase’s actual stopping point.
• Doubling the leading tone in the dominant chord, a tendency tone whose pull is sharpened, not supported, by doubling it.
• Tonicizing the dominant so thoroughly, with its own leading tone and cadence, that the ear hears a modulation rather than a pause within the original key.
• Cutting the dominant short instead of letting it sound long enough to register as the phrase’s destination.

• Hugo Riemann, Vereinfachte Harmonielehre (1893), On the half close — The dominant reached and left standing: tension displayed, not discharged.
• Ebenezer Prout, Harmony: Its Theory and Practice (1889), The chapter on cadences — The half close as the interior punctuation of the period.