Helpful video: When/how to use diminished 7th chords.

octatonic

I found this video as part of my piano studies.
It occurs that it might be useful for guitarists too.

It is pretty clearly laid out- if anyone needs to guitar fingerings then let me know and I can make some suggestions.
Diminished 7th shapes are much easier on guitar than piano, as it happens.

stratman3142

Interesting and educational. Thanks for posting. 

I'm sure this is already obvious to you, but I think of the diminished 7th chord as a dominant 7th with a sharpened root note. For example, C7 with a sharpened root note becomes C# diminished 7th. This is how I rationalise why I can chuck in a diminished arpeggio (a semitone above) over a dominant chord. Or an arpeggio built on any of its notes because (being symmetrical) the chord/arpeggio can take its name from any of its notes, as pointed out in the video.