UD#35 Anglular Symmetry: Diminished 7th Chords

Diminished seventh chords can be found in lots of different kinds of music. There are a few different ways to write them. Here are three different ways you might see a C diminished 7th chord written down: Cdim, Co, or Cdim7. For this lesson I will use this format: Cdim7 or Fdim7 throughout. Or I will write out the full name C diminished 7th or F diminished 7th. Most chord charts use the shortened form Cdim or Fdim.

Now for some cool facts…

4 COOL FACTS ABOUT DIMINISHED 7th CHORDS:

1. Only one shape!

You’ll only ever need one shape to play a diminished 7th chord on a ukulele. Here it is!

A diminished 7th chord is a four note chord that is completely symmetrical. Let’s build one and you’ll see what I mean.

We create a diminished 7th chord by stacking 4 notes, all a minor third (three frets) apart from each other.

Let’s do it by working up the C string on the uke:

Let’s start on open C. That’s will be the first note in our chord.

OK, let’s go three frets (a minor third) up the C string and pick another note: Eb (E flat)

That’s the second note in our chord. Now we have 2 notes: C and Eb. Let’s pick two more and we’ll have all 4.

Let’s go 3 frets up from the Eb. That’s a Gb note.

And three frets up from Gb is A. That’s our final note.

This gives us the four notes in a Cdim7 chord: C, Eb, Gb, and A

These four notes can be played with our diminished 7th shape at the second fret. Like this:

Challenge 1:
a) Repeat the same process above but start on the open G note and go up the G string. This will give you the notes in a Gdim7 chord. What are the notes in a Gdim7 chord?
b) Start on the open E note and go up the E string in the same manner as above.  This will give you the notes in an Edim7 chord. What are the notes in a Edim7 chord? Answers at the bottom of the page.

3. Diminished 7th chords repeat every 3 frets!

If we take this Cdim7:

And move it up three frets to the fifth fret we get this:

It’s the same four notes just in different positions in the same shape! Same chord!

NOTE: The smaller grey dots mark the 5th fret (one dot), 7th fret (two dots), and tenth fret (one dot).

Let’s try and move the shape three more frets up the neck. To the 8th fret:

It’s the same four notes just in different positions in the shape! Same chord again! Trust me that the same thing happens again when you move the chord shape up three more frets.

Wild and wacky…

4. Any note in the shape can be the root.

This is a Cdim7 chord. But it is also an Adim7, Ebdim7, and Gbdim7. Wild eh? Each of it’s notes can be it’s root. This makes it very easy to find a diminished 7th chord. You just move the one shape around until one of the notes in the shape is the note you are looking for.

Here is an example. Say you need a Bdim7 chord. Just move the diminished 7th shape around until one of the notes is a B note. Like this:

Bdim7 chord

You could also use the same shape three, six or nine frets up the neck if you need to. But this one will do.

Let’s find a Gdim7 chord. Just move the shape around until one of the notes is a G. Here it is:

Gdim7 chord

This version uses the open notes but you can see the shape remains the same. Again the same shape 3, 6, or 9 frets up the neck will be the same chord. But this one will do.

I hope your brain is not hurting. Here is a little task to check your understanding.

CHALLENGE:

Here you have the diminished 7th shape in three different positions. Incidentally these are the only three positions of the chord that you will ever need unless you have a specific reason for finding a diminished 7th chord up the neck. This is because of the fact that the diminished 7th chords repeat every 3 frets. Position 4 would be the same chord as position 1 and position 5 would be the same chord as position 2 etc.

Anyhow! See if you can answer the following questions:

Challenge 2:

Ex. Which of the three position above would be a Gdim7 chord?   Answer: Position 1, because it has the open G note in its’ shape

Here we go. Answers at the very bottom of the page.
1. Which of the three positions above would be an Fdim7 chord?
2. Which of the three positions above would be a Ddim7 chord?
3. Which of the three positions above would be an Adim7 chord?
4. Which of the three positions above would be an Bbdim7 chord?
5. Which of the three positions above would be an Edim7 chord?

Pretty technical this week! Hope you enjoyed it.

I will be back in two weeks with a video about the application of diminished seventh chords in jazz and other genres. Stay tuned!

All the best,

Guido

ANSWERS:
Challenge 1
a) Gdim= G, Bb, Db, E
b) Edim= E, G, Ab, B

Challenge 2
1.) position 2   2.) position 2.  3.) position 3  4.) position 1  5.) position 1

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