Understanding the Diminished Chord

In this chapter, we're going to look at the diminished chord.

What is a Diminished Chord?

The diminished chord is made up of three minor thirds, one on top of the other. The symbol for a diminished chord is either dim or a little circle.

The Peculiarity of Diminished Chords

The diminished chord is peculiar in that instead of there being 12 diminished chords, there are only really three. This is because for any diminished chord, any of the notes can count as the root.

For example:

• B flat diminished has all the same notes as:
  • G diminished
  • D flat diminished
  • E diminished

So, G diminished is the same as:

• B flat diminished
• D flat diminished
• E diminished

Similarly:

• A flat diminished is the same as:

  • B flat diminished
  • D diminished
  • F diminished

• A diminished is the same as:

  • C diminished
  • E flat diminished
  • G flat diminished

Good News for Practice

This is very good news because it means that you only need to practice three sets of scales and arpeggios, not 12.

Practicing Diminished Arpeggios

Here is the G diminished arpeggio in first position.

Note: You will see no logic in the fingering of these arpeggios, so you just have to practice them until your fingers know where to go.

Do the same with the A flat diminished and A diminished arpeggios.

Soloing with Diminished Scales

If you're soloing using a diminished scale, a pattern which is very useful is this one:

You can create a riff by combining triplets and arpeggio notes.

The G Diminished Scale

The scale of G diminished consists of the arpeggio notes, plus, for each note, a leading note a semitone below.

If you look at your fingers as you play a diminished scale, you may see a pattern emerge. The finger pattern you use on the G string is repeated on the D string, but a half position lower, and the same again on the next string.

Open strings complicate this pattern, but if you start on the G string in a higher position, you can use the same fingering four times as you ascend the scale.

Common Use of Diminished Chords

The most common use of diminished chords is as a passing chord between a I and a II minor 7. It works very well in this way because the diminished chord has a strong tendency to want to move and resolve up a semitone.

A diminished chord will often appear in this turnaround sequence.

Ignoring the Diminished Chord

In this context, where the diminished chord is only half a bar long, you can virtually ignore it.

For example: Here is a G major pentatonic phrase, which sounds fine over the A flat diminished.

Paying Attention to Diminished Chords

Here, on the other hand, we pay proper attention to the chord. It's pretty rare, but not impossible to find an extended section of diminished chord.

The bridge to the standard September Song, for example, goes something like this. The song is in the key of C, but there's no way you'd get away with bluffing your way through this as if it was a diatonic sequence.

Here's an example of what you could play.

Finally, here's an extended G diminished sequence, a bit more up tempo.