A diminished triad is one of the four triads used in music. Triads are 3-note chords built with intervals of a third and a fifth above a root note.
Diminished triads have a minor third and a diminished fifth, hence the name. It is built by adding a note a minor third above the root note, and a note a minor third above that second note.
You can add a diminished, minor or major 7th to the diminished triad to form the fully diminished, half-diminished and m-maj7♭5 chords respectively.
The diminished triad: chord formula
Take a look at my article on the 4 triads in music which includes the diminished triad. I cover each triad in detail so give that a quick read.
Basically, a diminished triad is built by stacking 2 minor thirds (m3) above a root note. That means that you add the note a minor third above the root note, then you add the note that is a minor third above the second note added (m3 + m3).
You can also view the diminished triad as a minor triad with a flattened 5th. Also, check out my music intervals article for descriptions of all the intervals used to build scales and chords.
All 7th-degree notes in major scales build a diminished triad. Let’s look at a B diminished triad in the key of C major as an example. The image below shows the notes in the B Locrian mode from the C major scale and the B Ultra Locrian from the C Harmonic Minor scale.
You can build a diminished triad from both scales. There are other scales that have diminished triads in them, but the half-diminished seventh chord and fully diminished seventh chord covered below have their origins in these two scales.
The chord formula for a diminished triad is:
Root note + minor third + diminished fifth = 1 – m3 – d5 = 1 – ♭3 – ♭5 = m3 + m3
The diminished triad is not very common in popular music (rock, country, etc.), though it is common in jazz and sometimes blues. You will see it in some popular genres, but usually, the dominant 7th is preferred since any dom7 chord contains the diminished triad.
Popular songs with a dim triad
Here are a number of songs that use the dim triad from the songbooks I own. Here are some examples that use the diminished triad:
Beach Boys: Caroline No, Friends, God Only Knows, Graduation Day, Let’s Go Away For A While
Beatles: Baby You’re A Rich Man, Blackbird, Hard Days Night, Michelle, I’m Happy Just To Dance With You, Penny Lane, Strawberry Fields Forever
Grateful Dead: The Other One, Dark Star, The Music Never Stopped
Led Zeppelin: Since I’ve Been Loving You
Sting: Mad About You
Simon & Garfunkel: Bridge Over Troubled Water
Jimmy Bryant: Stratosphere Boogie
Silverman’s Folk Song Encyclopedia, Vol. I & II: There are about 30 songs in each volume that use a diminished triad.
What is a half-diminished chord (m7♭5)?
A half-diminished 7th chord is just the diminished triad with a ♭7 added. It is notated as m7♭5 or with the ø symbol and a 7, e.g. Bø7 = Bm7♭5. By the way, that particular chord equals a m6 chord on the ♭3:
B-D-F-A (Bø7) = D-F-A-B (Dm6)
Bø7 or Bm7♭5 = 1 – ♭3 – ♭5 – ♭7 = 1-m3-d5-m7
The chord gets its name because the perfect 5th is diminished, but the seventh degree is not. There is a fully diminished chord that does have a diminished seventh degree (see below).
The half-diminished chord is a “… considerable instability”. – Henry, Earl and Rogers, Michael (2004). Tonality and Design in Music Theory, Vol. I
Half-diminished seventh chords only have that name because there is a fully diminished seventh chord. Otherwise, the chord would just be called a m7♭5 – I use “m7♭5” and not ø7 when I write out the chord.
Popular songs with a half-diminished chord
Here are some examples of songs that use the m7♭5 chord:
Beach Boys: Caroline No, Don’t Talk, God Only Knows, I Just Wasn’t Made for These Times, Let’s Go Away for a While
Grateful Dead: Cosmic Charlie, France, The Music Never Stopped, Terrapin Station
Bob Dylan: When I Paint My Masterpiece
Beatles: Penny Lane
Little Feat: Time Loves A Hero
Stevie Wonder: My Cherie Amour, You Are the Sunshine of My Life
To better understand what a half-diminished seventh chord is, let’s take a look at the fully diminished chord.
The fully diminished chord
The fully diminished chord (dim7) is one of the 2 symmetrical chords. Symmetrical chords and scales have notes in them that are an equal distance apart from each other.
Most people only mention the dim7 and augmented triad as chords that repeat after a certain interval but there are 4 other ones: 7♭9#11, 13#9 (no root or 5th), 7♭5, 13♭5#9 and 9♭5♭13. Know that tritones invert to tritones.
Dim7 chords consist of two tritones and the chord repeats every minor 3rd \ 3 frets. What that means is you can move the chord shape a minor third and it has the same notes in it but on different strings. Try it out for yourself – it’s really cool.
Like an augmented triad, the diminished seventh chord can have any of the chord tones as the root.
Bdim7 (B-D-F-A♭) = Ddim7 = Fdim7 = A♭\G#dim7
The chord is notated with a superscript circle followed by the number 7, e,g, Bdim7 = Bo7 = B-D-F-A♭. I just notate it as “dim7”.
It is called a fully diminished chord because the 7th is diminished:
A# = the major 7th of B
A = the minor 7th, or ♭7, of B
A♭ = the diminished 7th, or ♭♭7. of B
So the fully diminished 7th chord has the diminished 5th and diminished 7th, but the half-diminished 7th chord only has a diminished 5th.
Bo7 = B-D-F-A♭ = 1 – ♭3 – ♭5 – ♭♭7 = 1-m3-d5-d7 = m3 + m3 + m3
Bø7 = B-D-F-A = 1 – ♭3 – ♭5 – ♭7 = 1-m3-d5-m7 = m3 + m3 + M3
That’s the only difference – the half-diminished \ m7♭5 has the minor 7th, whereas the dim7 has the diminished 7th.
Popular songs with a fully diminished chord
Here are some songs that use the dim7 chord:
Allman Brothers: In Memory of Elizabeth Reed, One Way Out (outro)
Beatles: I’m Happy Just to Dance With You, Penny Lane, Strawberry Fields, Blackbird
Bob Dylan: Leopard-Skin Pillbox Hat, When I Paint My Masterpiece
Grateful Dead: Dark Star, The Music Never Stopped, Ship of Fools, Tennessee Jed, Deal
Eric Clapton: Mainline Florida
Reverend Gary Davis: Make Believe Stunt
Garth Brooks: Friends in Low Places
Albert Lee: Bullish Boogie
Jerry Reed: The Claw
Silverman’s Folk Song Encyclopedia, Vol. II: 6 songs with a dim7 on pages 21, 27, 30, 43, 63 & 362.
Other scales that build diminished chords
You can also build a diminished triad in the Melodic Minor scale on the 6th and 7th degree, and the Harmonic Minor scale on the 2nd, 4th, 6th & 7th degrees. If you like the diminished sound, here are some other scales that contain a dim triad:
- Major Bebop on the 2nd, 4th, 6th & the 8th scale notes.
- Blues Scale on the root.
- Half-Step Whole-Step Diminished scale (HW Dim) on the root and every other note after the root
The major bebop, and of course the diminished scale, build diminished chords, but most people don’t think of dim chords in the Blues Scales. It’s not standard to think of that scale as building diminished chords, but the notes are there to build them (dim & m7♭5).
Other diminished chords (m9♭5, m11♭5, m-maj7♭5)
There are three more dim chords that you don’t often see: m9♭5, m11♭5, and m-maj7♭5.
I like the minor 11 flat 5 chord (m11♭5) the best out of these other dim chords. Stevie Wonders uses a m11♭5 in “If You Really Love Me”. The chord formula for a minor eleven flat five chord is 1-♭3-♭5-♭7-11, e.g. Bm11♭5 = B-D-F-A-E.
A minor eleven flat five equals a m6 add 9 on the ♭3 and a 7sus♭9 on the 11 of the chord, and all those chords resolve nicely to the tonic chord. The m6 add9 chord is a staple in jazz, but I’m not so sure about m11♭5 or 7sus♭9 chords.
Bm11♭5 (B-D-F-A-E) = Dm6 add9 (D-F-A-B-E) and E7sus♭9 (E-A-B-D-F) – all resolve nicely to a C major chord.
The next diminished chord is a minor 9 flat five notated as m9♭5 (1-♭3-♭5-♭7-9) and is built from the Melodic Minor scale on the 6th degree. It has the same notes as a 7#5♭9 chord on the 9th.
Bm9♭5 (B-D-F-A-C#) = C#7#5♭9 (C#-F-A-B-D). The major 3rd of C# is E# or F, and the augmented 5th is G## or A.
And the last diminished chord is a dim triad with a major 7th called a “minor major 7 flat five” and notated as m-maj7♭5 (1-♭3-♭5-7). I assume only jazz guys use this chord. It comes from the Harmonic Major and Harmonic Minor scales. An example is:
Bm-maj7♭5 = B-D-F-A#
I think the m-maj7♭5 chord works best as a leading tone chord to a minor tonic chord. So Bm-maj7♭5 > C minor. Another great V7 chord to get you back to a minor tonic chord is the 7#9 chord on the V, e.g. G7#9 > Cm. If you play a G7#9 without the root it has the same notes as Bm-maj7♭5.
Table of B diminished chords
Here is a table of all the B diminished chords. The columns Equal Chord1 thru 3 are the other chords that contain the same notes.
|Chord Name||1st Note||2nd Note||3rd Note||4th Note||5th Note||6th Note||Equal Chord1||Equal Chord2||Equal Chord3|
|Bm11b5||B||D||F||A||E||–||Dm6 add9||E7sus b9||–|
Diminished chords for guitar
Here are the chord voicings I have for diminished chords, including open versions for the B diminished triad and every other B diminished chord. There are only 5 diminished chord shapes that have a 2 or 3-bar chord shape. Dim chords just don’t make barring them easy.
Take a look at the chord block chart below for all the symbols I use for chords on this site. Refer back to it as you need.
Closed Diminished triad & open B diminished triad guitar chord shapes
In my opinion, the dim triads are not good for strumming but are better played with hybrid picking or fingerpicking.
A good example is are the arpeggios at the opening of “Red House” by Jimi Hendrix. The chords in the opening measures are notated as E7 & Eb7 (if I remember correctly) but it’s actually G#dim & Gdim.
My favorite dim voicings are #’s 1, 2 & 5 and the #2 Bdim is okay.
Closed diminished 7th’s (m7♭5 & dim7) & open B diminished 7th chord shapes
Let me make some notes on some of the chord shapes below.
- The #4 m7♭5 chord shape is often taught as a dominant 9th chord which it shouldn’t be. It’s a great substitute for a 9th but it’s a half-diminished 7th chord. Keep that in mind if you ever encounter it.
- For the 3 dim7 chords, I mark EACH note as the root of the chord, because each note is, or can be, the root.
I like both dim7chords, #1 Bdim7, #’s 1, 3, 4, 5 & 8 m7♭5 and only #1 Bm7♭5.
All other closed and open B diminished chords (m9♭5, m11♭5, m-maj7♭5)
I like most of the chords below except for #2 Bm9♭5. It doesn’t sound good, probably because of the ♭5 ringing out over the open B note. It is included here in case someone finds a use for that dissonance. Also, I could not find 1 closed voicing for a m9♭5 chord – only open chords.
How to use the diminished triad and half-diminished chords
As I mentioned, I don’t often use the diminished triad or half-diminished seventh chord often because they are a part of the V7 & V9 chords. Let me show you what I mean:
B dim = B – D – F
G7 = G – (B – D – F)
Bm7♭5 = B – D – F – A
G9 = G – (B – D – F – A)
You can use either chord it in place of the V7 chord before going to the I or i chord. I do often use the D7 shape of a diminished triad in place of a 7 chord, especially in blues tunes.
How to use the dim7 chord
It’s common to use a dim7 chord 1 semitone above the V7 chord – replace G7 with A♭dim7 and it is a substitute for a G7♭9.
Or use it as a leading tone chord, e.g. Bdim7 > Cmaj. You can use the other tritone to go to a whole new key:
B-D-F-A♭ – The B & F in Bdim7 takes you C major, while D & A♭\G# take you to A major. But it can also resolve to C major, E♭ major, F#\G♭ major and A major. It sounds okay to resolve to the keys of E♭ & G♭ but it is a little weak.
But the fully diminished 7th chord will also resolve to the minor versions of those keys: Cm, E♭m, F#\G♭m & Am. Also, try using a dim7 chord a major second above a V7 chord.
Also, try it a 1/2 step above the IV7 chord before going to the I7 chord in blues. For example, a Bdim7 will resolve nicely to F7 as the I chord in F blues: B♭7 -> Bdim7 -> F7.
As a matter of fact, a Bdim7 will resolve to the major version of each chord tone: Bmaj, Dmaj, Fmaj, Abmaj.
Also, try moving one of the notes of the dim7 chord up a half step to a note in the resolving chord. For example, Bdim with the A♭ resolves nicely to A major or minor if the actual A♭ pitch in the chord moves to an A note on the same string 1 step ahead.
Jazz guys are the best at using dim7 and m7♭5 chords so I’ll leave it to them. I just stick with the normal chords of a key that contain the tritone.
When it comes down to it, let the tritone be your guide. You can use any chord that has the same tritone that is in the V7 chord. You would use it in place of the V7 to get you back “home” to the I. The B & F in the G7 and Bdim7 chords do just that, as do the chords Dm6, Fmaj7#11, etc.
For a really detailed examination of the resolving tendency of diminished chords, check out Diminished Chord – How To Use on the Simplifying Theory site.
It’s up to you whether you want to experiment with diminished triads and the various seventh chords. The fully diminished seventh is interesting, but I tend not to bother with the other ones, though I have found some m11♭5 voicings that sound fantastic.
Another option is to switch between B diminished and G dominant 7ths chords because they have the same function. Take a look at my articles: G7 Guitar Chords and Double Extended G7 Chords. Also, look at my Comprehensive List of Chords for all the chords that can be built from popular scales.
Mess around, experiment – there is no harm in learning more than you will ever need.
“It’s your mind, it’s your creativity, it’s your guitar, and most importantly, it’s your music – do what you want to do (just make sure it sounds good)”. ~ quote by Kernix