Mandolin Chord Shapes: Diminished 7th
In today’s Mandolin Chord Shapes series we’ll continue our look at the Diminished chords with Diminished 7th chords (I sometimes refer to as “fully diminished” which I don’t believe is “technically” correct – but it makes sense to me). You can find the full series here. Also, if you enjoy this post or have any questions, please comment below.
What is a Diminished 7th Chord?
Diminished 7th chords are the 1 b3, b5 and bb7 of a key. Yes, that is a double flat 7th which is the same note as the 6th. The two main notations for diminished chords are either “°” or “dim7”.
The Diminished 7th is a unique chord in that each note in the chord could be considered its root. This works because the chord is built on b3rd intervals.
- 1 to b3 is a b3rd (i.e. A to C)
- b3 to b5 is a b3rd (i.e. C to Eb)
- b5 to the bb7 is a b3rd (i.e. Eb to Gb)
- bb7 to the 1 is a b3rd (i.e. Gb to A)
The below example in the key of A may help.

The first measure is the 4 notes that make up the Ao7 – A C Eb Gb. The second measure shows those same notes moving up the fretboard as a chord. The first has A as the lowest note, the next has C, the next Eb, and the last has Gb. Notice that the chords are the same notes just in a different order. Each measure, the lowest note moves to the highest note – so the low A note to start moves to the high A in the next chord. Since all the notes are the same, that means that Ao7 is also Co7, Ebo7, and Gbo7 (or Fo7).
3 note vs 4 note diminished 7th chords
Diminished 7th chords are four note chords – so playing all the notes is usually a good idea. However, depending on the song etc, you can often play just a three note variation instead of the full chord. I recommend learning the full four note chords even if you only plan to play three note variations mostly. You’ll get more for your practice time learning the full chord shapes and have a better understanding overall.
What’s the “starting fret”?
The shapes here are general moveable patterns – meaning there’s no specific starting fret. Simply find the root note on the fretboard and that will tell you what fret you should start on etc. Using a fretboard roadmap like this can help.
Colors

The colors are just quick short cuts to avoid having to include the numerical values in the positions (saves a bunch of time!).
Mandolin Chord Shapes

Diminished 7th Root on the G – Shape 1
I use this diminished shape the most. I find it’s the easier variation to use in most songs. You can use pretty much any three strings to create a three note variation on this chord if you’d like. If you’re playing solo, including the root is a good idea in most cases. When in doubt, dropping the b5 is usually an okay thing to do.
I sometimes play the three note variation G A and E which skips the D string. You lose the b3rd which isn’t ideal, but still works.
Generally fingers are:
G String – Middle
D String – First
A String – Pinky
E String – Ring
Diminished 7th Root on the G – Shape 2
I honestly rarely use this shape in its full form, but it can be handy as a three note variation. If I’m playing with others, I use three note variation with the D A and E strings. This leaves out the root, which hopefully someone else is getting! The other three note variation on the D A and E string can work too but leaves out the b3rd which isn’t ideal for this chord in my opinion.
Generally fingers are:
G String – First
D String – Middle
A String – Ring
E String – Pinky


Diminished 7th Root on the D- Shape 1
Not much different from the G – Shape 1 above, but if you’re in to the skipping strings thing – you can play G D and E (skipping the A). That sort of takes away the “diminished 7th” feel because you don’t get the bb7, but can work in many settings.
Generally fingers are:
G String – Middle
D String – First
A String – Pinky
E String – Ring
Diminished 7th Root on D – Shape 2
The only real difference between the G shape 1 and this shape is the three note variation on the G D and A is a nice combination.
Generally fingers are:
G String – Middle
D String – Pinky
A String – Ring
E String – First


Diminished 7th Root on A- Shape 1
Pretty much the as G shape 1 still. Even the three note variation.
Generally fingers are:
G String – Middle
D String – First
A String – Pinky
E String – Ring
Diminished 7th Root on the A – Shape 2
Again… pretty much the same as the other Shape 2’s. The three note variation on D A and E is a good one to use here.
Generally fingers are:
G String – First
D String – Middle
A String – Ring
E String – Pinky


Diminished 7th Root on the E – Shape 1
Surprise, it’s the same as the other Shape 1’s. Here the three note variation using G D and E is probably best.
Generally fingers are:
G String – Middle
D String – First
A String – Pinky
E String – Ring
Diminished 7th Root on the E – Shape 2
If you’re still surprised this is the same as the other Shape 2’s, I’m not sure what to tell you.
Playing the G D and A string variation works well here.
Generally fingers are:
G String – First
D String – Middle
A String – Ring
E String – Pinky

Wrapping Up
I hope the mini-Mandolin Chord Shape series on Diminished Chords has helped. Here’s a link to the full series. I’ll be taking a break from chord shapes for a few weeks and moving back to the Circle of 5ths.
If you like’d this post or have questions, feel free to leave a comment below. If you’d like to take a deeper dive into chord shapes look click here for more information on private coaching. If you like this free content and would like more of it, considering donating to my site here – donations really help keep things going!
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