Watch the The Diminished Chord online guitar lesson by Robben Ford from Chord Revolution: Foundations
I want to talk about the seventh chord. I've almost skirted it, because it is a diminished triad, and therefore its uses are far more limited than your basic major and minor triads. So once again, the harmonized G major scale. Two chord, three chord, four chord, five chord, six chord, seven chord, to the G again. So instead of playing it up here I'm going to play it down here. Same notes. That might be a little bit of a spread for some people. I don't know what to say about that other than just play it in a different position on the guitar, a different key. But I'm going to give it to you here. So that's the seventh chord, E minor's the sixth chord, seventh chord and then the octave. Now a seventh chord - we're not talking about like G7 or C7 - it's the seventh chord of the harmonized scale. Now it is a diminished triad, and its function is basically as a five chord. It's almost like playing D7, G. That's the function of the chord. I hope you can hear that.
In the key of G, it's basically a D7 chord. The intervals are minor third intervals. That's a minor third as opposed to a major third. Anything diminished you can keep going in minor thirds. You could move that triad, diminished triad. You could move it in minor thirds and resolve it to G. It's the F# on its way to G. That's where the chord is headed, back to G. So it's just a really nice thing to know and remember about anything diminished. And again, this is a diminished triad. Three notes in minor thirds. You can move it in minor thirds, all over the guitar. It's serving the function of a five chord. It's like going D to G. Another interesting note about this is that it also resolves very nicely to E minor. So it's like functioning as a five chord for a different chord, which I just find interesting. You could do that same arpeggiated diminished triad and resolve to E minor. So again, I rarely use that chord voicing. I will use something a little bit different. I'll play a different kind of a diminished chord. I just want you to know that that seventh chord is a diminished triad and that it can be moved in minor thirds all over the guitar. It resolves back to the key that we're in, G. It also resolves really nicely to the relative minor chord, which in the key of G is E minor.