Enhancing The Mediant Chord

In the last part we learned how to apply the mediant (iii) chord in the diatonic chord scale.

Now let's find out how we can modify the iii chord to give us more variation when writing our basic chord progressions. Variation is good because it gives you more creative options, freeing up your expression as a songwriter.

I'm aware I've probably repeated that a hundred times now!

Remember, a lot of the chord modifications we use in these lessons can be learned in the chords section of the main site.

The major III chord

As you know from the last part, the iii chord is naturally a minor chord. What do I mean by "naturally"? This is a whole subject in itself (diatonic theory) and I won't side track into that now. It's difficult to even summarise without causing possible confusion!

Anyway, you'll soon realise that using a major III chord can be just as compatible with the other chords in the scale as using a minor iii.

The mediant chord's function, in relation to other chords in the scale, doesn't change when you make it a major chord.

For example, below is a typical I - iii - vi - IV progression in the key of E major (E major being our tonic I chord). You'll probably have heard this progression used in a lot of songs!

I - E major	iii - Ab minor Fret 4
vi - C# minor Fret 4	IV - A major

Click to hear >

Now let's turn that iii chord into a major III chord to hear the difference...

III - Ab major

Fret 4

Click to hear >

So there's quite a bit more tension in the chord, enhancing its unresolved quality. It has a certain tendency to move to the V or (like in this example) vi chord, but that's by no means the only options. There are no "rules" as such.

The idea is to experiment with both minor and major versions in your progressions and take your pick, or even interchange them.

III as a dominant 7th chord

Remember in the supertonic (ii/II) lesson, we learned that the II chord could be enhanced further by using a dominant 7th (e.g. E7, D7, C7)? Well, we can do exactly the same with the III chord.

Let's hear that same I - iii - vi - IV progression from above, but this time with a dominant 7th III chord. I'm just using a standard barre chord for this...

III7 - Ab dominant 7

Fret 4

Click to hear >

Now, when the chord is modified like this, you may see it written as III7, or II7 if it's the II chord. This is why roman numerals are used (otherwise we'd be writing 37 or 27 - too confusing!).

Let's just take a look at another example of using the dominant 7th III chord, this time with an A string root note (different chord shape).

I - A major Fret 5	III - C#7 Fret 4
IV - Dmaj7 Fret 5	ii - B minor Fret 2

Click to hear >

Other mediant chord modifications

I always find jazz a great genre for discovering interesting chord extentions used in the positions we've been learning.

With the III chord, a typical jazzy alternative is to use an augmented 7th chord (e.g. Baug7). Here's a common (although rather excited) use of it, in an ascending pattern from the major I tonic up to the V7 chord...

I - F# major Fret 2	III - Bbaug7 Fret 6
IV - Bmaj7 Fret 7	V - C#9 Fret 9

Click to hear >

So yet even more tension is added to the III chord by using both the dominant 7th and the augmented (sharp) 5th. If you're scratching your head wondering what "augmented" and "7th/5th" mean, this is all covered in the chord theory series.

As always, keep experimenting with different chord combinations and with modifying each chord (major/minor, dominant 7th/major 7th etc.) based on your knowledge from prior lessons.

By the end of the next part, we'll have finally built our foundations! You'll see why it was so important to spend a lot of time on this as you begin to build on these foundations with chords outside the scale...

< Guitar Songwriting Contents

footer for guitar lessons page

Online Guitar Lessons