Anatomy of a Diminished Chord

Diminished chords are often ignored by folk singers, and it's a shame.  They can add wonderful coloration to tunes, and they make you look like you really know the guitar, too, cuz most other guitar players won't recognize the chords.

The basic formula for a diminished triad is R - b3 - b5.   Another way to look at it is that the triad is built of "stacked thirds," where the 2nd note is a b3 above the root, and the 3rd note is a b3 above the 2nd note.

A fourth note may be added by adding another b3 above the 3rd note.  That will turn out to be the 6 note of the scale.  The 6th note is actually a bb7 (flatted flat 7), so maybe this version is a dim7 -- I don't know and don't care.  The form of diminished chord shown below is really easy to use.

And just to finish the cycle, a b3 above the 4th note is the octave of the root.  So the diminished note is a perfect set of stacked b3 notes.  Look at the common diminished form below and study the chart at the bottom to see how this works.

diminished = R + b3 + b3 + b3

Here's the very common 4 note movable diminished chord. Is it a plain diminished? Is it a 7th diminished? Is it a 6th diminished?
1st Finger on 4th Fret.  The notes from low to high are F# - D# - C - A. This chord may be named after any note in the chord. One other unique feature of this chord is that it may be played up and down the neck by moving it 3 frets at a time, allowing for more movement.

Here are two more diminished forms.  Take a look at how they are formed and named.

From Music Theory for the Short Attention Span   © FolkBlues.Com