Watch the Diminished Scale online guitar lesson by Bruce Arnold from Total Modal

The Diminished mode is our first 8 note mode and the 1st mode that is symmetrical. It is made up of 1/2 steps and whole steps. Look at the chart that shows the structure of the Diminished mode to see its symmetry. Also check the common chord progressions listed on the same page to find out how to apply the mode to some common chord progressions.
The Diminished Mode has no avoid notes. Diminished chords are usually found as passing diminished and use a passing diminished mode. See the Modes organized with chord types to see the passing Diminished Modes. Students find that the Diminished modes are hard to remember and hard to hear and apply, so be patient with them. There are really a lot of cool ideas you can get from the mode; it just takes practice and patience.