So, what are “borrowed chords”? Well, these chords are not borrowed in the sense that they have to be given back! Rather, borrowed chords in music theory are kinda stolen from other keys with the same root note.
Understanding the Harmony
If you haven’t already, you’ll probably want to read up on how to harmonise a scale before getting into this. When you harmonise a scale, you’re creating the chords that fit with that scale (made out of the notes in the scale). What we’re going to do today is to take more than one scale (with the same root note), and mix the chords up a bit- for more interesting results.
For example, when we harmonise a C major scale, we get these chords:
C – Dm – Em – F – G – Am – Bm7b5
I – ii – iii – IV – V – vi – viiø
Which means that any song containing just those chords will be in the key of C.
Now we also need to take a different scale that also starts on a C note (i.e. it has the same root note). What happens if we harmonise, say, the C natural minor scale? Remember: you can do this with any scale you choose, as long as it starts on a C note.
Harmonising C natural minor scale produces these chords:
Cm – Dm7b5 – Eb – Fm – Gbm – Ab – Bb
i – iiø – bIII – iv – bv – bVI – bVII
Putting the two together
Next comes the fun part! Using the two sets of chords together can produce interesting results. For example: if you take this, fairly common, chord progression:
I – vi – IV – V
Which, in the key of C major would be these chords: C – Am – F – G. If you play that one yourself I think you’ll agree that its pretty common, and pretty average…but what happens if you substitute one of the chords for one from the C natural minor scale?
Say, instead of “I – vi – IV – V”, we replaced the sixth (“vi”) chord from the major scale (i.e. the A minor) with the sixth chord of the minor scale- which would be a bVI, or A flat major? Our chord progression is now much more interesting!
C – Ab – F – G
The chord progression above is actually used fairly often, too, by bands such as Nirvana and many others. Its just way more interesting than the boring set of standard chords we started with!
Another good example is the “I – bVII – bVI – bVII” progression (remember: major chords are shown by uppercase letters in the Roman numerals).
In C, again, this progression would be:
C – Bb – Ab – Bb
The Bb and the Ab are, again, taken from the minor scale with the same root note (also known as the “parallel minor” scale).
Taking things Further
The great thing is that you can do this with any scale that starts on the same note. Lets look at the C dorian mode as another example.
The chords of the dorian mode are:
i – ii – bIII – IV – v – viø – bVII
…and I must stress at this point, that modes don’t generally work with chord progressions, so you’re not going to want to make an entire chord progression from these chords, but they are there in theory for us to use.
From this set of chords, we can “borrow” the bIII- which, in C dorian would be an Eb chord- and the “v”- which, in C dorian would be a G minor- to make this progression:
C – Eb – Gm – G
Soloing over these types of progressions is also pretty easy- you just change the scale to fit the one the chords are borrowed from!
So, now its time for you to give this a go yourself, and see what interesting new chord progressions you can come up with!