The interval structure of a diminished scale is as follows: whole-step, half-step, whole-step, half-step, whole-step, etc. Or it can be half-step, whole-step, half-step, whole-step, etc. It just depends on the situation. Use your ear to determine which way sounds best to you.
Take a look at the A diminished scale below and notice that because the interval pattern is so repetitive, this could also be a C diminished scale, a Eb diminished scale, or a Gb diminished scale.
This fact makes it easy to move a diminished scale around the fretboard.
A – B – C – D – Eb – F – Gb – G# – A
The following patterns show different fingerings for an A diminished scale (or C, or Eb, or Gb diminished scale).
Form 1
Form 2
Form 3
Form 4
Practice Exercises
Play through each finger pattern ascending and descending using a slow even tempo.
Move the forms around the fretboard.
Staying with the same root, and at a slow tempo, play continually in and out of the different forms with no breaks.
With a friend, or using a tape recorder, play these scales against full-diminished chords. The sound will quickly become easy to recognize.