Primary Triads (Natural Minor) and Their Functions ① / Music Theory Lesson

Author: sleepfreaks

Understanding the Functions of Natural Minor Diatonic Chords

This time we will take a look at using natural minor diatonic chords to create a sense of “story” in a chord progression.
We’ll keep the differences between major diatonic chords in mind as well as the differences between the 3 types of minor chords.

We took a look at the function of major diatonic traids in our 28th article.
To create a song with a sense of “story” in a natural minor key, it is important to understand the function of each chord.
Like major keys, randomly lining up chords doesn’t always lead to the best results, and it is important to have a sense of development (beginning, development, twist, end).

Primary Triads in a Natural Minor Scale

As the first step, lets take a look at the 3 most important chords – the primary chords.
We will use the keys of C major and C minor as examples.

First we have the major key.


In the scale degree names of a major key we have the words:

  • Tonic
  • Subdominant
  • Dominant

Chords built upon these 3 notes are called the primary triads/chords, and their importance were mentioned in our 28th, 29th, 30th, and 31st article.

Next lets take a look at the scale degree names of the natural minor scale.

※You may see it written without b marks (III, VI, VII), in lower case letter (i.e. ⅲ), etc.

Here we also have

  • Tonic
  • Subdominant
  • Dominant

these same key words.

Lets create diatonic chords on top of these.

  • Triads
  • mtsd_diatonic_triad

  • 7th
  • mtsd_diatonic_triad

Lets take a look at the difference between major and minor scales.
The primary chords in a major key were all major type chords (contains M3rd interval): major traid / major 7th / dominant 7th.



On the other hand, the primary chords in a (natural) minor key are all minor type chords (contains m3rd interval): minor traid / minor 7th.です。



We’ll start by keeping these differences in mind.

The Function of Primary Triads

Next, lets take a look at the function of these primary chords.

  • T=Tonic

    The most central chord of the key. It has a powerful sense of stability, and is often used as the first and/or last chord in a progression.
    * You may often find it not used as the first chord of a song to create a specific feel

  • SD(or S)=Subdominant

    It functions somewhere between the T and D chord, and adds flavor and development to a chord progression.
    Moving from the T to the SD gives a sense of development and gives almost a sense of “floating” within the chord progression.
    When used before the D, it creates a smooth and powerful flow when leading back to the T.

  • D=Dominant

    It has the most powerful pull back towards the I=T=Tonic chord.
    When moving from the Dominant back to the Tonic, it creates a sense of relief from the tension
    and a strong sense of completion (in particular when returning to the I chord).
    To create more tension, use the V7 over the V chord.

Excluding the “Dominant chord”, these work the same in major and natural minor chords.
The dominant (dominant minor) in a natural minor key Vm/Vm7 don’t contain a leading tone or tritone, and doesn’t have a strong sense of “tenseness” meaning it doesn’t have a strong pull back to the Tonic.

  • ❇︎ Minor primary chords are often written as Tm (tonic minor), SDm (or Sm) (subdominant minor), and Dm (dominant minor), so keep these in mind.

Lets take a look at the primary chords in each natural minor key as well.
Displayed in Blue (T or Tm), Green (SD or SDm), Red (D or Dm)

  • Triads
  • mtsd_matrixtetrad

  • 7th
  • mtsd_matrix_triad

The Change of Functions in Relative Keys

Lastly, lets take a look at the difference in function for relative keys as well.

In our 8th article we saw that C major and A minor are relative keys.
In this case, the chords found from the scale notes are the same, but the functions change between the 2 scales.

  • C Major Diatonic Chords (7th)
  • C_diatonic_tetrad

  • A Minor Diatonic Chords (7th)
  • am_diatonic

By keeping this point in mind, it will make figuring out keys when analyzing songs much easier as well.

Next time, we will take a look at cadences in natural minor keys, as well as take a look at using leading tones in this key.

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.