Chord Theory can seem like tricky topic but by focusing on some basic chord shapes, it’s a lot easier. In this series, I review a variety of mandolin chord shapes for various chord types. Check out some of the previous lessons in the mandolin chord shapes series here.
In today’s review we’ll start our look at the Diminished chords – specifically the Diminished Triad which is the base for other diminished chords (similar to how the major and minor triads are bases for their extensions like 7th chords).
What is a Diminished Triad?
A diminished triad is simply the 1 b3 and b5 of a key. The two main notations for diminished chords are either “dim” or “o“. Diminished chords are unstable chords that can add a lot of suspense and tension to progressions. Often they are used as passing chords (or tones) to create some interesting movement. Very simply stated, a “passing chord” is a chord that moves you from one place to another. Diminished chords generally want to resolve to the next chord in the scale (usually the root).
Where to Use Diminished Triads
There’s a lot of potential uses, but generally anywhere you want to add tension and drama, these are good options. There are some “tried and true” uses of diminished chords and I provide 2 below- but I encourage you to experiment around.
- Between any two chords a whole step apart. For example if a progression goes from G to A, adding in a G#dim chord would create a chromatic movement from G to A (adding the G#).
- A substitute for the 5 (or V) chord. In a standard ii V I change, you can replace the V with a diminished chord. For example, Dm G C could change to Dm (D F A), D#dim (D# F A), C (C E G). The sub of the D#dim gives the chromatic movement D, D#, E. This works will in songs like Salty Dog Blues, Swing 42, or It’s Only a Paper Moon.
These Chords Look Familiar…
Diminished Chords share a lot with 7th chords (aka Dom7). As a general rule, by adding the note a 3rd below the root of a diminished chord, you’ll have a 7th chord of that note. In example, playing B D F would be a B Diminished chord. If you add the G note, you’d get G B D F or G7. This works for all Diminished Triads and can be a really handy short cut. I’d suggest taking note of these as they can be great quick substitutions. I often will “think” of a 7th chord that could be a diminished – for example, C#dim (C# E G) is really similar to A7 (A C# E G).
3 note vs 4 note Mandolin chord Shapes
In my diagrams I’ll mostly display 4 note chords, though I will explain 3 note variations when appropriate. While you can certainly play just 3 note chords and be great (a la Jethro Burns for example), learning the 4 note variations gives you more bang for your buck without really any more effort. Plus, knowing the 4 note chord allows you the flexibility to drop one note to get a 3 note variation if you want – giving you a lot more options with less to memorize.
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.
Shape names
I may be giving up on the quirky names for now. If you have any suggestions, post them in the comments 😉
Root on the G (and E) – Shape 1
This is a great shape to get down for Diminished Triads. While I do play the full 4 note chord often, it’s much more common for me to use one of the 3 note variations instead.
The variation using the G D and A strings is a lot like a dominant 7th chord (without the root). If you played this variation where the Root was on the 4th fret of the G, you’d have a B diminished triad (B D F) – but you’d also have a G7 chord without the root. Which brings up a simple substitution to keep in mind – you can generally replace a Diminished Chord using the 7th chord by adding a note 3 steps below the root of the diminished chord.
The variation using D A and E strings is a really useful chord shape too. Aside from being simple, it’s a great movement chord. For example, this works great as a substitution for the V in a ii V I progression – try playing A minor, followed by A# diminished then B major (this would be a ii V I with the V subbed for a #iidim chord. Note the chromatic walk up from A to B.
Generally fingers are:
G String – Middle
D String – First
A String – Ring
E String – Pinky
Root on the G (and A) – Shape 2
Most often use the 3 note variation of this chord using the D A and E strings, but adding the double Root with the G string can be useful from time to time.
The 3 note variation on the D A and E strings is really similar to the 7th chord with a root on the G as well. If you fretted this chord with the Root on the C# (for C# diminished), you’d be playing a rootless A7 chord as well (the notes C# E and G).
Generally fingers are:
G String – Pinky
D String – First
A String – Ring
E String – Middle
Root on D – Shape 1
This is an easy 4 note chord to hit and the double b3 gives it a funky quality. Plus, there are two 3 note variations that are super useful.
Playing the G D and A strings is similar to the Root on G shape 2 chord, just moved down a string. Similar, if you started with the Root on the 4th fret of the D (the F#), you’d be playing the a rootless D7 chord as well (A F# C).
Playing the D A and E strings is another great shape. Similar to the other 3 note variation, when you play these three notes, you are also playing a rootless D7 (F# C A).
Generally fingers are:
G String – First
D String – Ring
A String – Middle
E String – Pinky
Root on D (and E) – Shape 2 – The Diminished Chop
This chord is a lot like the Big Chop chords but diminished. While this isn’t a chord shape I use too often, it does come in handy when you want to use a descending chord progression (like for intros / outros for jazz tunes). I find I use the 3 note variation with the G D and A strings most often here for a descending outro.
Try starting with the root on the 6th fret of the D string (Abo) then moving the b5 and root back one fret (so playing C#, G, B or C#m7b5) then back another fret (C F# B or C7b5), then another (B F B or B5) then play an A chord with the root on the 2nd fret of G (A C# E) to resolve.
Generally fingers are:
G String – Pinky
D String – Ring
A String – First
E String – Middle
Root on the A – Shape 1
I use the 3 note variation with the G D and A strings all the time. Though the variation with D A and E is another that has a lot of similarities to 7th chords -making it easy as a sub.
If you play the 3 note variation on the D A and E strings so the Root is on the 4th fret of A (or C#) you’d have E C# G, that could also be looked at as an A7 chord without the root.
Generally fingers are:
G String – First
D String – Middle
A String – Pinky
E String – Ring
Root on the A – Shape 2
I really only use this shape in very specific scenarios – like when there’s a descending line where I can move the b5 and root back stepwise to get to the root chord. This is very similar to the Root on the D Shape 2 – but just moved up a string.
There’s no good way to play the full 4 note chord in my opinion, but the 3 note variation can come in handy from time to time as an outro or intro similar to the Root on the D shape 2 (you can try the same basic example I provided for that shape here).
Generally fingers are:
G String – n/a
D String – Pinky
A String – Ring
E String – First
Root on the E (and D) – Shape 1
This is a really fun shape. I like using the full 4 note chord a lot, but the three note variation using G D and A is really useful too. It’s pretty similar to the Root on D Shape 1 but instead of two b3’s you have two root notes.
If you played the 3 note variation with the Root on the 4th fret (F#), you’d also be playing a rootless D7 chord (A F# C).
Generally fingers are:
G String – First
D String – Pinky
A String – Ring
E String – Middle
Root on the E (and G) – Shape 2
I probably don’t really ever play the full 4 note chord here honestly. The 3 note variation using the D A and E strings however can be really useful, especially when you have a descending bass line on the D string.
If you play the 3 note variation using D A and E strings so the Root was on the 3rd fret of the E (so G) and then moved the b3rd back one fret, you’d be playing A7 without the 5th (A C# G).
Generally fingers are:
G String – Ring
D String – Pinky
A String – Middle
E String – First
Wrapping Up
Diminished chords are great chords that often get a bad wrap as too complex. I hope this has helped clear up some of the mystery of these chords.
While these are most commonly found in more jazzy styles of music – they can exist in a variety of tunes. For example, in the bluegrass standard Salty Dog Blues, you can substitute the VI chord for a I#o and get a fun ascending chromatic line.
The next two posts on the Chord Shape series will further these and explain more about the Half Diminished (or m7b5) and Diminished 7th chords.
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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