Knowledge for Using Non-Diatonic Chords / Music Theory Lesson

Preparation to Understand Non-Diatonic Chords

This time, in conjunction to our knowledge on major and minor (3 types) keys, we will take a look at 1 way to use non-diatonic chords.

Please check out the image below first:

Lets try analyzing this.

As we can see, we have a chord that isn’t a diatonic chord.

However, we can understand the III using our knowledge on the 3 minor key types.
We added a melody to this below:

In this case the melody doesn’t have muddy avoid note sounds so using just diatonic chords would work as well.

The example below uses the same melody with only diatonic chords.

The feel is very different even when using the same melody.
Though the Em→Am isn’t bad, the E→Am sounds nostalgic, and the D→G has a different sound as well.

As seen, there are various chords to choose from when adding a melody to chords.
Try listening to both examples with this in mind.

The previously analyzed songs「Fly Me to the Moon (In Other Words)」「Les Feuilles Mortes」

Now that we know the minor II-V-I,
we can see how the III / III7 is built into the major key.

How about the other parts:

Lets focus on the areas circled in black and check the diatonic chord chart.

This chart doesn’t have this chord, and isn’t the V of the relative minor key or part of the II-V-I progression.
Lets take a look at the chord progression before and after it.

If we look at the the “I” next to the mystery chord, we can see that it is the V→I of that key.

• Key=F
  C7→Fmaj7
  V7→Imaj7

• Key=G
  D→G
  V→I

As seen, the area circled in black contain the leading tone of the key and function as a “V→I” progression to the chord that follows.

Use this knowledge to help understand chords that may have seemed out of place when analysing music.
You may make some new realisations.

Of course, not all chords will fall into these categories.
Next time we will take a deeper look at non-diatonic chords.

Article Writer: Kazuma Itoh

After moving to the USA at 18 years of age with a scholarship from Berklee, he completed a 4 year study focused on song writing and arranging there.
Using this knowledge, he works across a variety of fields from pop music, film music, and more.

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