Borrowed Chords and Mode Mixture

The previous lesson left the scale by treating a chord as a temporary tonic. This one uses a different entrance.

Borrow a chord from the parallel key — from C minor if you are in C major, from C major if you are in C minor. Since the tonic is shared, the destination does not move and only the coloring changes. This is a borrowed chord, or mode mixture.

Take care to distinguish this from relative keys. C major and A minor share a key signature and differ in tonic, so they share chords from the outset. Borrowing happens between C major and C minor, which share a tonic and differ in signature.

What changes — ♭3, ♭6, ♭7

Set C major beside C natural minor and only three notes differ.

	Third	Sixth	Seventh
C major	E	A	B
C minor	Eb	Ab	Bb

A borrowed chord is one containing one of those three: ♭3, ♭6, or ♭7. Put the other way around, when Eb, Ab, or Bb turns up in a major-key passage, borrowing is the first thing to suspect.

Here are the borrowed chords used most often in C major.

Chord	Notes	Note borrowed	Character
iv	F Ab C	♭6	most common; a soft sinking
♭VI	Ab C Eb	♭6 and ♭3	an abrupt change of color
♭III	Eb G Bb	♭3 and ♭7	floating
♭VII	Bb D F	♭7	open, rock-flavored
ii°	D F Ab	♭6	turns ii into a diminished triad

The minor subdominant — one ♭6 and nothing else

The most frequent is iv, the minor subdominant. In C major that means making the F chord an Fm.

Only one voice moves in Fig. 1: the alto falls a half step from A to Ab. The bass stays on F and the soprano stays on C. The change in what you hear is nonetheless unmistakable.

The working element is the descending chromatic line A → Ab → G. The major sixth degree drops to ♭6 and then lands on the dominant. If a rising half step, the leading tone, feels like being pulled, a falling half step feels like tension being let go.

IV → I against iv → I

▶IV → I▶iv → I▶IV → iv → I

Check: Both move to the tonic from a chord built on F. The first is straightforwardly bright; the second sinks just before arriving. The difference is one note, Ab. The third passes through IV on the way to iv, which makes the half-step fall from A to Ab audible as it happens. That falling half step is the thing usually described as poignancy.

staying in major

Check

Applying mixture to ii (Dm) in C major gives D F Ab. What kind of chord is that?

minor triaddiminished triadaugmented triadmajor triad

Check answer

♭VI, ♭III, and ♭VII

Three major triads can also be borrowed from minor: ♭III, ♭VI, and ♭VII. All three are diatonic in minor (III, VI, VII), and importing them into major adds accidentals.

Placing ♭VI immediately before the dominant is the standard use. The bass falls a half step from Ab to G, which is the same descent onto the dominant found in the Neapolitan and augmented-sixth chords of the next lessons.

♭VII behaves rather differently.

The ♭VII in Fig. 3 is Bb D F, which contains no leading tone B. Classical harmony expects a leading tone before the tonic, so this progression sits outside that expectation.

Whether to call it borrowing or modal writing depends on your standpoint. A C major scale with a flattened seventh is Mixolydian, so describing it as Mixolydian practice often fits better. The reason I – ♭VII – IV – I is a staple of rock and folk is precisely that it lies outside classical harmony. The modes themselves are the subject of Unit 9.

Borrowing the other way — the Picardy third

So far major has been borrowing from minor. The reverse also happens.

End a minor-key piece on a major triad on the tonic. That is the Picardy third. In C minor the final Cm becomes C.

Two ways to end in minor

▶Ordinary cadence▶Picardy third

Check: A cadence in C minor. The first ends normally on Cm. The second raises only the third of the final chord, from Eb to E. One note changes, in one chord, and the character of the close is entirely different. The first ends dark; the second finds light at the end of a dark road.

iv – V – i

Note also that minor keys are already borrowing the moment they use harmonic minor. The V of C minor is a major triad (G B D) because B has been imported, which means the harmony of minor keys is a product of mixture from the start. Unit 2’s account of three minor scales was the other side of this same fact.

Check

Borrowing ♭III (Eb G Bb) into C major introduces how many notes from outside the scale?

noneonetwothree

Check answer

▶ Check the diatonic chords of C minor A borrowed chord is one of these imported into C major. Find iv, ♭VI, ♭III, and ♭VII and play them Diatonic Chord Reference →

Borrowing is an operation for lending color. The next lesson takes up a chord that lies on the same continuum but has been given a name of its own: the major triad on ♭II, the Neapolitan chord.