Choosing chords to approach an imperfect cadence

The most basic type of imperfect cadence is I-V, and Bach generally approaches this from Chord V7b or its clse relative, chord viib. Example 1.10.1 demonstrates some of the possibilities.

The first three progressions in this example are all from the same chorale and show how Bach sought to achieve variety, even when faced with similar cadences in the same key. All three patterns work equally well in major keys. Progression iv uses vii7 as an approach chord which, in a minor key as here, is a diminished 7th chord.

Other approach chords include I, IV or VI – the choice depends on creating contrast with the first chord of the cadence as well as harmonising the given melody.

Sometimes the first note of an imperfect cadence is a minim, as shown in example 1.10.3 I, or there are two crotchets of the same pitch before the last chord of the cadence, as shown in ii.

In such cases it is often not possible to use different chords for the two crotchet beats as we did in the perfect cadences on the previous page. However, as you can see in Ex.10.3, Bach doesn’t merely write a minim in all parts for the first chord, or repeat it exactly on the second crotchet beat. Instead he maintains a sense of movement through the use of passing notes and/or additional harmony notes. Notice the way in which the downward octave leap in the bass of cadence I gives impetus to the second beat of the bar without altering the harmony.

In cadence ii Bach provides variety by moving from chord I to chord ib below the repeated C in the melody This progression, from root position through the first inversion of the same chord with the bass rising through quaver passing notes, is often used by Bach – and not only in cadences.

The first of these progressions uses V7b as an approach chord. He seconds has ivb.

Complete Activity 1.10.

Add bass parts and chord symbols (but not inner parts) to harmonise the following melodic patterns, which should each end with an imperfect cadence.