What is modal interchange?
Modal interchange is a technique where chords from the parallel minor are introduced into a major key (and vice versa). For example, in C major you can use chords from C minor: bIII (Eb major), bVI (Ab major), bVII (Bb major).
Common borrowed chords
In major, the most common borrowings are: iv (minor subdominant), bVI and bVII (from Aeolian minor), bIII (from natural minor). Each adds a minor shade without disrupting the tonal center.
- iv — minor subdominant (Fm in C major)
- bVI — major chord on the lowered 6th degree (Ab in C major)
- bVII — major chord on the lowered 7th degree (Bb in C major)
How to use modal interchange
A borrowed chord usually replaces its diatonic counterpart. For example, iv replaces IV, bVII replaces V or vii°. The key rule: the tonal center must not shift. The listener should hear an "unexpected color," not a key change.
Examples in songs
Radiohead "Creep": I-III-IV-iv — the IV→iv shift creates a signature effect. The Beatles "In My Life": use of bVII in major. Nirvana "Lithium": alternating major and minor chords on the same degrees.