Over the past lessons, we've been building the diatonic chord scale - a
naturally occuring system of chords built on the 7 degrees of the major
We've just built chords on each degree as
opposed to playing them as single notes like the scales you use for
With the chord scale nearly complete, let's now add in the iii
chord, known as the mediant
in diatonic theory. Just think of
the 3rd chord in the 7 chord scale we're building...
like in the other lessons, I'll first go through the iii chord's
position in relation to the tonic (I)
and other chords in the scale, then we'll look at
how we can use the iii chord in various combinations with the other
chord positions we've learned.
iii chord, as represented by the lower case numerals, is naturally a minor
chord. The first thing we need to do is listen to how it
its related tonic chord, no matter what key you're playing in.
say our tonic chord was C major.
Its related mediant iii chord would
therefore be E minor
(since E is the third note of C major).
We'll look at exactly how we work this out in more detail in a minute,
but first I just want you to get a taste of the sound of this
What's interesting about
the iii chord is it's rarely used in the above way, to resolve straight
back to the tonic chord. It has more of a tendancy to lead either up to
the IV chord, fall to the ii chord or move to the vi chord. It is
used more as a link to other chords on a journey away from the tonic.
(using C major as our tonic
see how the iii chord fits in to the chord interval pattern we've
been building in past lessons. Remember, each of these positions
represents the root note from which we can build chords, whether barre
or other movable shapes. More on chords types in the chord section of the site.
Note that the 1st diagram slightly overlaps the next...
both examples, look at where the iii chord appears in relation to other
chords in the scale. Try and memorise these relationships. For
one fret (one semitone) down from the IV
chord on the same string.
two frets up (one whole step) from the ii
chord on the same string.
on the E string, iii
appears diagonally to the left on the next string up (two
remember... these interval relationships are movable, just like any
scale! The entire scale keeps its relative formation as you change key,
being defined by the tonic chord.
This is the most basic way to
understand the relationship between chords in a scale, since once you
know the root note intervals between them, you can start to build
chords around those same intervals.
Chord progressions involving the iii chord
now we have 6 chords from which we can draw various
combinations (progressions). I know several songs that simply use I ii
iii IV (or in reverse) as a straight sequence. I'm sure you can be more
inventive than that! ;)
A few points:
Progressions don't always need to start on the
You don't have to use the iii chord at all if
you don't want to, but the option is there!
These are all major key progressions (hence the
look at minor key progressions another time.
usual, experiment with your own combinations and don't forget to try
modifications of chords that we've looked at in previous lessons, such
as minor iv chords. There's more and more to think about as our
creative options expand, but that's good! Keep referring to past
lessons to refresh your memory.