Cadences

Every phrase of a chorale ends at a pause, and every pause needs a cadence. Plan them first: they fix the key and the shape of the whole harmonisation.

The four cadences

Cadence	Chords	How often in Bach
Perfect	V(7) to I	The most common, and always at the end
Imperfect	Any chord to V	Common at the ends of inner phrases
Plagal	IV to I	Rare
Interrupted	V to vi	Occasional, usually in the middle of a chorale

Rules for cadence chords

• Both chords of a perfect or imperfect cadence are in root position.
• The chord of the cadence must match the key in force at that point. If the melody has a chromatic note near the pause, the cadence is probably in a new key.

Good ways to approach a cadence

• ii6/5 to V(7) to I. The 7th of ii7 is prepared and falls to the leading note.
• Ic to V to I. Ic (the cadential 6/4) goes on the strong beat, with the bass doubled.
• IV or ii6 to V.
• A 4-3 suspension over V. See the lesson on decoration.

Common mistakes

• An inverted chord at a perfect or imperfect cadence.
• A retrogression at the cadence, such as V to IV.
• Labelling the cadence in the home key when the music has modulated. A cadence onto A in D major with G# present is A: V to I, not D: V.