Diminished Chords

The diminished chord is a triad consisting of notes found
at the first (I ), minor third (iii ), and diminished fifth (v° ) intervals
of the major scale.
The diminished triad can also be said to be built by
finding the root, the next note which is a
minor third from the root,
and the next note which is also a minor third
interval from the previous note.
The diminished triad is a diatonic chord of the first
degree of the Locrian mode of the major scale.
From the tonic, the notes of the chord are every third note
of the Locrian mode, played at the same time.

The diminished chord is
played by simultaneously sounding the tones
of the first, fourth, and seventh notes
of the chromatic scale- or;
a root note, a note 3 frets higher than the root, and
a note 6 frets higher than the root.

You can add depth and variation to a diminished chord
by adding unison notes
or I (1st ), iii (min 3rd ), & (dim 5th )
notes of higher and lower octaves.