Diminished

The diminished scale is a symmetrical scale that consists of the notes R, M2, m3, P4, A4, A5, M6, and M7.

You’ll notice several things about the Diminished scale. First, diminished is an 8-note scale, so one of the note names is repeated (in this example, it is the 4th). You will also notice that the diminished scale ascends in a series of whole steps and half steps.

So the diminished either ascends w,h,w,h,w,h,w,h or h,w,h,w,h,w,h,w. Since the diminished is a symmetrical scale, it repeats itself in minor 3rds. C, Eb, F#, and Ab diminished are all the same scale. This means there are really only 3 diminished scales: C diminished, C# diminished, and D diminished. All other diminished scales are repeats of the same notes.