The chord symbol for a diminished chord is o or dim. The full name of this chord is diminished seventh but it is usually referred to as a diminished chord. Here is the most common chord shape for the diminished chord.
EbB or AB or CB or F#B
This diminished chord shape uses only the first four strings and has four different names. The diminished chord can take its name from any note in the chord, e.g., the shape to the left contains the notes E flat (Eb), C, A and F sharp (F#). So this shape can be either Ebdim, Cdim, Adim or F#dim. If this shape was moved up one fret it would be Edim or C#dim, Bbdim or Gdim, etc. To locate any diminished chord simply play this diminished shape so that it includes the letter name of the chord.
Rhythm Pattern
Proceed to Progressive Guitar Method: Bar Chords .