What are diminished chords?

Jul26

Diminished chords are very cool, and easy to understand. Diminished chords serve a cadential function just like a dominant 7. Let’s look at a dominant 7 chord construction in the key of C:

In the key of c the dominant chord would be a G

Chord tones: G B D

T make it a dominant 7 add the F:

Chord Tones: G B D F

Now let’s look at the diminished chord in the key of C which would be a B Diminished:

Chord tones: B D F

To make it a diminished 7 or a minor 7b5 which is how it is most commonly referred to add the a

Chord tones: B D F A

Now if you look closely at the two chords

G7: G B D F

Bm7b5: B D F A

The only thing separating these two notes is the A and the G, so they can be used interchangeably to perform the same function.

There are in reality two types of diminished chords The Half diminished which is the minor7b5: B D F A. And, there is also the full diminished chord: B D F Ab

Here is a form for each of the diminished chords.

   ------ ------ ------ ------
   ---3-- ---3-- ---1-- ---1--
   ---2-- ---1-- ---2-- ---2--
   ---3-- ---3-- ---2-- ---1--
   ---2-- ---2-- ------ ------
   ------ ------ ---2-- ---2--

Just like all bar chords these are universal shapes and can be moved anywhere on the fretboard and you will come out with a diminished chord as long as the shape is retained.

One of my favorite tunes that utilizes the diminished chord is Autumn Leaves. Check out the lesson Jazz Comping V for an arrangement of Autumn Leaves. You should probably get yourself a Jazz real book and go from there.

Well, I hope I have been helpful, please feel free to email me with any questions.

About Logan L. Gabriel

Logan L. Gabriel lives in southern New Hampshire where he is an active teacher. He has released a CD entitled Tree and Leaf: Original Music for Solo Guitar.

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