The diminished triad is an essential part of functional harmony! Without it, you wouldn’t have diatonic chord progressions or dominant chords. Mastering the diminished triad is necessary to become the best jazz musician you can be.
Luckily, we’ve prepared this article covering everything you need to know! We’ll cover what the diminished triad is, its many uses, and where these shapes physically sit on the guitar.
We’ll start by covering some music theory basics and then learn how to use diminished chords to enhance your jazz chord playing and improvisational skills.
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Table of Contents
What Does The Major Scale Have To Do With Triads?
Everything! Let’s take a brief moment and start from the beginning.
You probably already know the major scale formula:
- W-W-H-W-W-W-H
- C-D-E-F-G-A-B-C
Most basic chords are constructed using tertiary harmony. This means we build chords based on thirds. Let’s start with C and find its third using the major scale formula.
C-D-E
Let’s find the third of E using the major scale formula.
C-D-E-F-G
This gives us a three-note chord based on thirds—or a triad. In this case, we have a C major triad. Therefore, triads are three-note chords built using the intervallic structure of scales. All triads contain a root note, a third (major or minor), and a fifth (perfect, diminished, or augmented).
When we say diatonic triads, we specifically mean triads built from the scale degrees of the major scale.
There are three types of triads that we can make from the major scale:
- Major Triads
- Minor Triads
- Diminished Triads
Augmented triads are not diatonic (meaning they don’t occur in the major scale) but occur in other types of scales. For more on augmented triads, check out this augmented triad guide for guitar.
Let’s look at these triads on the staff:
- C Major Triad: C-D-E-F-G-A-B-C
- D Minor Triad: D-E-F-G-A-B-C-D
- E Minor Triad: E-F-G-A-B-C-D-E
- F Major Triad: F-G-A-B-C-D-E-F
- G Major Triad: G-A-B-C-D-E-F-G
- A Minor Triad: A-B-C-D-E-F-G-A
- B Diminished Triad: B-C-D-E-F-G-A-B
Within the major scale, we have three major chord triads (C, F, and G), three minor chord triads (D-, E-, and A-), and one diminished triad (Bdim). Let’s analyze each triad type to understand why each is different.
Building a Major Triad
The interval relationships between C-E and E-G reveal the formula for a major chord triad.
We need a major third up from the root and a minor third up from the third scale degree.
- Root + M3 + m3 = Major Triad
To learn major triad shapes on guitar, check out our guide to major triads on guitar.
Building a Minor Triad
The interval relationships between D-F and F-A reveal the formula for a minor chord triad.
Minor triads are intervallically the inverse of major triads. We need a minor third from the root note and a major third from the minor third scale degree.
- Root + m3 + M3 = Minor Triad
To learn more about minor triad shapes on guitar, check out our minor triad guitar guide.
Building a Diminished Triad
Finally, we come to the diminished triad. You’ll notice that there is only one diminished triad in every major key, and this diminished chord is built from the seventh scale degree (B in this case).
Diminished triads are different because they are built from two minor thirds, unlike a major or minor chord.
- Major: M3 + m3
- Minor: m3 + M3
- Diminished: m3 + m3
Our B diminished chord is spelled B-D-F. Built from two minor thirds, the interval between the root note and the fifth scale degree is a diminished fifth. This gives diminished chords their unique qualities. They contain a tritone, which means these chords have wide utility in jazz.
Now that we’ve fully explored the diminished triad let’s talk about how to use diminished chords when playing chords or improvising lines.
Memorizing Diminished Triad Shapes
We’re almost ready to dig into diminished triad shapes on the guitar! But first, we have to understand the concept of chord inversions.
What Are Triad Inversions?
The root of any chord is often notated on the bottom of the chord structure. Generally, when people picture a G-diminished chord in their head, they’ll see G on the bottom, Bb (3rd) in the middle, and Db (5th) on top. However, the chord’s root doesn’t have to be on the bottom of the chord structure.
It can be in the middle or on the top and still be a G-diminished chord. When a chord has its root on the bottom, its third note in the middle, and its fifth note on top, it is in root position.
When the root moves to the top, leaving the 3rd on the bottom and the 5th in the middle, it is in 1st inversion. Finally, if you move the third to the top so that the 5th is on the bottom and the 3rd is in the middle, you have a second inversion.
Since we’ll be learning diminished chords all over the fretboard, we’ll encounter root position, 1st inversion, and second inversion triads.
BEFORE YOU CONTINUE...
If music theory has always seemed confusing to you and you wish someone would make it feel simple, our free guide will help you unlock jazz theory secrets.
Diminished Chord Shapes on the First String Group (E, A, and D strings)
Diminished Chord Shapes on the Second String Group (A, D, and G Strings)
Diminished Chords on the Third String Group (D, G, and B Strings)
Diminished Chords on the Fourth String Group (G, B, and E Strings)
What Are Diminished Triads Used For?
Diminished triads have a whole range of applications in music theory. In this section, we’ll discuss how to use them to improve your jazz chord playing.
Here are common uses for diminished chords in jazz:
Diatonic vii° Chords
The most obvious use would be to play a diminished triad over a chord based on the seventh scale degree in a given key. Though most jazz players would opt to use the seventh chord version, a half-diminished seventh chord, sometimes players will opt for a basic triad when outlining the changes.
Here are the first four bars of the jazz tune There Will Never Be Another You in concert Eb.
If we perform harmonic analysis, the tune starts on the I and moves to the diatonic viiø chord in the third bar. In cases like this, a player may use a basic Ddim triad instead of a full seventh chord.
For more on fully diminished seventh chords on the guitar, check out our article on diminished seventh chords. Check out our article on half-diminished seventh chords on the fretboard to explore the half-diminished seventh chord.
Rootless Dominant Chord Voicings
Speaking of seventh chords, every dominant seventh chord has a diminished triad within it. Seventh chords are built from the root note, a third, a fifth, and a seventh (hence the name).
Because there are four notes minimum in every seventh chord, at least two triads are present within each—a triad built from the root, 3rd, and 5th, and a triad built from the 3rd, 5th, and 7th.
For example, a G7 chord can be broken down into two triads: a G major triad and a B diminished triad
There are many playing situations where the root is redundant. If you have a bass player, most roots you play are. Some players will choose rootless voicings depending on the specifics of a performance.
You can play rootless dominant chord voicings by playing a diminished triad from the third of any dominant chord you encounter.
Diminished Passing Chords and Diminished Chord Cycling
Jazz pianists and guitarists will often use diminished chords when comping over dominant chords. This is because diminished chords have a unique dominant function. Let’s explore.
Diminished Chord Cycling
You can take any diminished chord on the guitar and move the shape up or down a minor third. Repeat this process to cycle through all the notes in a fully diminished seventh chord.
If you start on Bdim, the notes are B, D, and F.
Move all the notes up a minor third, and you’ll have a D-diminished chord. The notes are D, F, and Ab.
Repeat, and you have an F-diminished chord. The notes are F, Ab, and B.
Another minor third brings us to Ab diminished, whose notes are Ab, B, and D.
Finally, one more time takes us back to B diminished.
How To Use The Diminished Cycle Over A Dominant Chord
Guitarists can use this cycle to move rapidly across the fretboard over a dominant chord. This device is often used by guitarists who want to infuse more movement and energy into their comping patterns.
Here is a common ii-V-I comping device that cycles diminished chords over a dominant chord:
The four notes in the diminished chords used above are all the same: B, D, F, and Ab. This diminished chord figure hits all the important notes in a G7 chord and the b9 for extra crunch.
- Ab is the b9
- F is the 7th
- D is the 5th
- B is the 3rd
That means you can cycle diminished triads starting from any dominant chord’s 3rd, 5th, 7th, or b9.
Ready To Master Improvisational Tools Like The Diminished Triad? Join The Inner Circle
This article was just the tip of the diminished iceberg! There are so many ways you can utilize diminished chords and the diminished scale to bring richness and complexity to your jazz playing.
If you are ready to take your playing ability and jazz theory knowledge to the next level, check out the Learn Jazz Standards Inner Circle. The Inner Circle has everything you need to give your jazz chops a serious overhaul.
From monthly jazz standards studies to an abundance of workshops, masterclasses, and courses on improvisation, harmony, and jazz theory, we have exactly what you need to bust through practice plateaus and get to the next level.