Minor 3rd Chord Substitution

Question by Istvan

Hey Marc!

First of all thanx for Your amazing website!

In progressions like the first 4 bars of “Just Friends”, in the key of G the 3rd bar is a cm7 and the 4th is F7 leading to Gmaj. Can I play over these 2 bars as they were II and V in the key of G while the comper still plays cm7 and F7.



M-A’s Answer:

Hello Istvan,

In one word: yes. You could play in G major scale during the Cm7-F7.

It would create a sort of “harmonic forward motion” effect, all the tension (such as the F#, the E and the B) within G major scale would resolve once the Gmaj7 chord is sounded.

It’s a nice kind of shortcut, but for the sake of being thorough and “harmonically correct”, you should really seek to play over Cm7-F7-Gmaj7. It’s a typical progression in jazz called the “Backdoor Progression”.

I discuss it here : https://www.jazzguitarlessons.net/jazz-chords-2.html (in the “Backdoor” topic)

The substitution principle I address in the article is the opposite of what you’re asking. (It’s like using the Cm7-F7 scales over Am7-D7). The reason why I’m insisting on learning the real thing that is the backdoor (instead of always using the shortcut) is because there’s a very important relationship between the chords.

Think about this:

In what key is Cm7-F7? Bb major! It’s in fact, the relative major of … G minor scale. (-:

So, if you learn to play Cm7-F7-Gmaj7 in improvisation, you’re actually familiarizing yourself with a nice “minor to major relationship that is SO important in jazz.

I hope this helps,

Marc-Andre Seguin

Old Comments for Minor 3rd Chord Substitution

Nov 15, 2011
Chord Movement
by: Jim Kipler

Hi Marc!

Just want to commend you on your great guitar site. Moving along, a lot of players don’t understand, that tunes often change keys many times within the tune itself. Take a tune like “Misty”. It starts on the I Chord Ebma7 then Bbm7 to Eb7, II to V in Ab to Abma7. Continuing, Abm7 to Db7 not resolving to Gb. That’s just a smattering, but I’m sure you get the idea. I think you said it best with your “Just Friends” advice. Cm7 to F7 is II to V in Bb. I don’t think this complicates soloing, just be aware of the different keys you pass through. Thanks again Marc for all that you do.

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