BORROWED CHORDS

A borrowed chord is an altered chord in the current key, which is also a diatonic chord in the parallel key. For instance, if the current key is the C major key and instead of a diatonic chord from the C major key, a diatonic chord from the C minor key appears, then it is a borrowed chord. It is also a borrowed chord if the current key is the C minor key and a instead of a diatonic chord from the C minor key, a diatonic chord from the C major key appears. In both cases, we are borrowing a diatonic chord from the parallel key.

Borrowed chords in major keys

The next figure shows how to find the borrowed triad chords in the C major key. In it, the diatonic triad chords in the C major key are compared to the diatonic triad chords in its parallel C minor key. For simplicity, only the often used diatonic triad chords in the C minor key are shown. The borrowed triad chords in the C major key are chords that are diatonic in the C minor key and are not diatonic in the C major key. They are marked in red and annotated also in the C major key. We would have the same chord qualities, the same harmony annotations and different chord roots if we chose some other major key. This is the reason why we can examine only the C major key.

Figure: Finding the borrowed triad chords in the C major key (the borrowed triad chords are marked in red)

The next figure shows how to find the borrowed seventh chords in the C major key. The procedure is similar.

Figure: Finding the borrowed seventh chords in the C major key (the borrowed seventh chords are marked in red)

Common examples of borrowed chords in a major key are those that result from lowering the sixth scale degree. As an example, the next figure shows the beginning of  Chopin’s Nocturne in Ab major. 

Figure: The beginning of Chopin's Nocturne in Ab major

From this example, we can also learn the importance of observing the notes throughout their whole duration to see which of them sound together. If we rewrite the rhythmic values of the notes from the beginning measure using the ties (see chapter Ties), so that it is easier to see which notes sound together, we can easily see that there are four chords in the beginning measure.

Figure: Harmony analysis of the beginning of Chopin's Nocturne in Ab major

The two harmonies that contain the lowered sixth scale degree (Fb) are: the minor triad chord on the fourth scale degree and the half-diminished seventh chord on the second scale degree. We can find these harmony annotations in the first two figures of this chapter. Thus, they are borrowed from the minor key. In this case, the Ab minor key. 

Borrowed chords in minor keys

The next figure shows how to find the borrowed triad chords in the C minor key. In it, the diatonic triad chords in the C minor key are compared to the diatonic triad chords in its parallel C major key. The borrowed triad chords in the C minor key are chords that are diatonic in the C major key and are not diatonic in the C minor key. The figure shows all the diatonic triad chords in the C minor key, not only those that are often used. The reason is: we must be sure that we shall exclude all the diatonic chords in the C minor key from the borrowed chords in the C minor key. The borrowed triad chords in the C minor key are marked in red and annotated also in the C minor key. We would have the same chord qualities, the same harmony annotations and different chord roots if we chose some other minor key. This is the reason why we can examine only the C minor key.

Figure: Finding the borrowed triad chords in the C minor key (the borrowed triad chords are marked in red)

The next figure shows how to find the borrowed seventh chords in the C minor key. The procedure is similar.

Figure: Finding the borrowed seventh chords in the C minor key (the borrowed seventh chords are marked in red)

The borrowed chords in the minor keys are not as important as the borrowed chords in the major keys. The reason is that the sixth and seventh scale degree can be raised in the minor keys. This gives the minor keys built-in possibilities for varying notes and chords which can be used by composers to make more expressive music. 

A common case of the borrowed chord in the minor keys is the Picardy cadence. It was named after the region in the north of France. It occurs when a composition, written in a minor key, ends with the major triad chord on the tonic (instead of expected minor triad chord on the tonic). This was very common at the time of Bach and many Bach’s compositions that are written in a minor key end in this way. Also, some of Chopin’s Nocturnes follow the same practice. For instance, the next figure shows the ending of Bach’s Prelude No. 6 in D minor, from Well-Tempered Clavier, book I. The current key is the D minor key, but the final chord is the D major triad chord (it contains the note name F# instead of F). 

Figure: An example of the borrowed chord at the end of the Picardy cadence

In the figure, we see that the final chord is the diatonic triad chord on the first scale degree of the parallel major key (the D major key). Thus, it is a borrowed chord. 

The chord preceding the final chord (the A dominant seventh chord) also occurs in the D major key. However, since it is created by raising the (commonly raised) seventh scale degree of the D minor key, it is not a borrowed chord.