Forum - Banjo Ben Clark

Diminished chord Notation

@BanjoBen (or other experienced forum members),

Can you help me with a notation question.

I am writing a song in the key of G. I have a place where I want to step up from a C (IV) Chord to a D (V) chord… using a C#, E, G diminished chord as a transition.

Since a diminished chord, by definition, is 3 semi-tones (3 piano keys) - or 1-1/2 steps…

As you know, the 4 notes in this diminished chord are: C#, E, G, A# within 1 octave and repeats up or down to the next octave.

I also know from theory, the only “natural” diminished chord in any MAJOR key is the 7th (F#, A, C in the key of G major) - which doesn’t apply here.

Therefore, how would this typically be called out in the key of G for notation purposes within the G progression?

So I am not sure what to call it as an altered number chord in they key of G???

Is it a 4 altered chord (c#-dim)? Is it a 6 chord (e-dim), a 1 chord (g-dim) or an altered 2 chord a#-dim?


Not really all that hot on music theory and I am not sure I understand your query but if your asking what the diminished chord in the Key of G is that would be B…

Check out this link. I find it helps me answer 90% of my theory queries.



Thanks for the resource. I will check it out… but in the key of G Major, the B chord (or iii chord) is minor, not diminished… as the B triad is B, D, and F#.

In a major key, the 7th tone (in this case, F#) is always the only natural diminished triad using F#, A and C notes - in the triad.

In my question, the diminished chord I intend to use is NOT built in the 7th tone triad… so I am not sure how it would be notated by way of chord notation.

I appreciate the support @Archie. I will look after lunch.

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Opps Sorry Will I didn’t look properly.

B is the diminished chord in the Key of C.

F# is the diminished chord in the Key of G

@BanjoBen @Mark_Rocka or @Fiddle_wood are more knowledgeable than I.


I guess it wouldn’t matter what you called it since the notes are all the same. If I was trying to play from the chart though, I would expect the diminished chord to be named by the bass note. Does that make sense?


It does @mharrison43.

Thanks Mike. My only though is… diminished chords are really unusual as the triad is all 3 semi-tones… which tend to give it a harp-like quality so determining the base note isn’t as fixed as:

  • Major (root, 4 semi-tone interval, 3 semi-tone interval)

  • Minor (root, 3 semi-tone interval, 4 semi-tone interval)

  • Augmented (root, 4 semi-tone interval, 4 semi-tone interval)

Even as the augmented has the same intervals (2 whole steps), there is a triad that makes it lopsided within the octave. This is also true with Major and Minor Triads as they don’t have the same intervals).

A diminished though… always has 3 semi-tone intervals and with 12 notes in an octave, the exact same 4 notes just keep repeating… so the base note is harder to identify - excluding the 7th tone in the Major scale or the 2nd tone in a minor scale - which are natural diminished chords as discussed with @Archie above.

In my case… It really might not matter the exact root note… and name… BUT, I’d be surprised if there was not a chord progression notation that was standardly used to reflect this.

Just curious, is all…

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Yes…your description is right-on as I understand it. My thought on the bass note pertains to playing guitar or bass on the piece. The bass note would really determine the sound of the chord in the context of the song’s progression…curious indeed! :grinning:


@mharrison43 Mike,

I am sure I did a poor job of explaining the quandary but I am glad you grasp the issue.

Worse yet is that it is a transitional chord: I am using the c to c#… to pull the listener’s ear to the D note root of the following D major (V chord) before proceeding to end the phrase on the G note root of the G Major (I Chord).

It is a common practice and adds a really rich sound… but I just cannot figure the proper notation on the transitional chord progression.

Side note: I was taught to use Roman Numerals for Chord progressions like this (for triads):

Key of C
I Chord = Root = C , E, G (CAPS denotes MAJOR)
ii Chord = D, F, A (small letters denotes minor)
iii Chord = E, G, B (minor)
IV Chord = F, A, C (MAJOR)
V Chord = G, B, D (MAJOR)
vi Chord = A, C, E (minor)
vii° Chord = B, D, F (diminished - should be small letters with a degree sign)

AUGMENTED uses CAPS and a ‘+’ sign
EXAMPLE: C+ = C, E, G# Triad

I don’t know if Roman Numerals are used anymore.

I noticed that Nashville System doesn’t bother… Just using the number to denote the chord… much quicker to write!

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I won’t say I’m real knowledgeable about this but
many just denote diminished as “dim”

these basically repeat every three frets so the bass note doesn’t necessarily identify the chord if you’re using a substitute voicing…

I think I said that right…


Hey Will,

Are you talking about using the transition chord with the intent of changing the key? If so, what chord are you starting with, what is the transition chord, and what key are you changing to?



Nope… @Treblemaker,

No change of key Jack. The transition is still solidly in the key of G (through the whole song, in fact)… but the diminished chord is going from a C (4) chord to a D (5) chord.

The notes in the progression is C (with E in the melody) to C# in the end of the measure (with E, C#, E in the melody line) that then lands on D in the following measure.

The purpose of the C# is to pull the listener’s ear toward the D note that is coming…

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Even though I didn’t play it very well at all and the recording is poor, you can hear the chord in the following rhythm track:

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I think you’re referring to what you’re doing at 26 and 48 seconds and so on. Is that correct? Sounds nice by the way. (Good tension waiting for a resolution).

So my question is what notes are you grabbing at the moment you play that tense chord? I’m guessing the name of the chord for purposes of notation would be based on those specific notes which make up that chord. That was probably about as clear as mud.

This may require Ben’s input. I know his ear could dissect this in a second.


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You have it right Jack. It is the chords that are leading up to the suspended break.

The diminished chord is C# E (I believe I played those notes)…

The melody sung over it is E C# E and resolves to a D when I played DSus4 to D Major

All the notes in the diminished octave is C#, E, G, A#.

I know the notes… but it is the progression notation that throws me off… Is it a 6dim (as E os the 6th tone in G)?

I don’t think it can be tied to the G because it isn’t linked to the 1 chord… and C# and F# are not tones in the natural key of G.

Listen to the melody sung so nicely by @Grace at 0:21 and 0:45. Don’t be confused that the rhythm is in 4/4 but @Grace sang the melody as we experimented in 3/4 time.


I just write the name of the note in the bass then put a “dim” after it.


I have also seen a lowercase “o” in superscript.


Thanks @BanjoBen,

Honestly, I tell you that there was no connection to the latest “Jesus Paid it all” when I wrote the music.

Then, I went back and listen to the lesson… and much you my amazement, you actually covered the dim chord in the lesson!

Ok, so you didn’t discuss chord progression notations, but the structure was all there!:smirk:

It did make me consider afterwards… perhaps I “heard” that wonderful chord progression in my mind from hearing the preview of the lesson… and then fused it subconsciously into the song we were writing (“The Day Death Died” in the Easter Song thread).

All I know is that it seems to fit so well in both.

Well, thanks for the advice. :facepunch:

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