Using Degree Names (4 note chords) and the Existence of Non-Diatonic Chords / Music Theory Lesson

Author: sleepfreaks

Using 4 Note Chords and the existence of Non-Diatonic Chords

This time, we will be utilizing 4 note chords and their degree names in real world situations.

Though we will take a brief look at non-diatonic chords,
we will be focusing on the same song in a future article so think of this as more of an introduction to this concept.

In addition, the information from the previous article will be crucial, so be sure to brush up your knowledge if you have not done so!


Analyzing Songs Using Degree Names of 4 Note Chords

First lets give this sample a listen.

This is an expert from the first half of the world famous jazz standard “Fly Me to the Moon (In Other Words)”.
It has a highly sophisticated sounding chord progression, and is usually played with more of a swing feel.

In this article, we will be taking a look at this progression.

First we must figure out the key.
If you have notation, this can be done by seeing the placement of the # or b.

  • Melody


  • Chords


The key without any # or ♭ is…


C major, or A minor.

However, doesn’t it feel like it shifts from a bright major feel
to a cooler and darker minor feel

Lets take a look at the chord names as well.


There’s a particular minor darkness towards the last 3 bars.

Lets think back to our article on minor 7th chords.

  • Minor chords have a dark tonality
  • Minor 7th chords have a dark yet shimmery complexity

We took a look at these tonal characteristics.

In this song, by changing the last chord to an Am this may become clearer.

  • Last chord as Am
  • Last chord as Am7 (original)

When listening to music or making your own, try paying attention to hear these slight differences in sound.

Using ♯ and ♭ that are Not Found in the Key

If you don’t have notated music, you would need to use your ears to find the melody and chord progression.

  • Melody


  • Chords


Here you may have realized this again, but there is a G# in the music despite it being in the key of C major / A minor.
In addition, there is a B♭ found in the C7 chord as well.

When we look at the diatonic chords for the Keyof C major…


7th Chords

There is no C7 or E7 chord to be found.

If you have already tried to analyze music on your own,
you may have come across non-diatonic chords and struggled to define them correctly.

What we can tell here, is that the world is full of songs that
use chords that are not diatonic chords – a.k.a. non-diatonic chords.
✳︎ Of course, there are plenty of great songs that utilize only diatonic chords

We will look further into detail on non-diatonic chords in a future article,
so lets focus on how to analyze them in just this context for this issue.

Similar to when we looked at triads, we will use the chart to switch out the chords with their degree names.



We have analyzed all the chords using our prior knowledge except for the chords marked with a “?”.
How do we define the “?” (non-diatonic chords).

The process behind this is fairly simple.

Like mentioned in our 21st article, the roman numeral of each degree name is related to it’s placement in a scale.


Using this knowledge, even if it is not a diatonic chord,
lets try applying a roman numeral to it by what note it is in the scale.

Because we are in the key of C major, C7 is I7, and E7 is III7.


This completes our analysis.

Why it Sounds like the Key Changes

The reason that the end of this part from Fly Me to the Moon sounds dark can be discovered by understanding minor and diatonic chords, as well as the function of each chord to see them from different perspectives.


We will take a look back on this song when we move onto this concept,
so be sure to stay tuned and remember this song when the time comes!

In our next article, we will be taking a look at using 4 note chords for some chord progression examples as well as changing the key of a song.

Article Writer: Kazuma Itoh

講師 伊藤
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.