The VI-II-V-I progression

[Jean-Michel G]

The “Rhythm Changes” progression is one of the most famous harmonic progression in jazz. Its name comes from the standard jazz song “I Got Rhythm” composed by George Gershwin in 1931.
It goes as follows:
|I vi |ii V | played twice and followed by
|I I7 |IV iv |I V |I |
The whole thing is usually played at a fast tempo.

But the opening two bars: |I vi |ii V | can be found in various shapes and forms throughout music history, from Baroque to pop, jazz, rock, etc. It is also called the “circle progression” because vi – ii – V – I progresses in descending fifths. In G major, for example, we have: Em – Am – D – G with the roots E, A, D and G descending by fifths.

That progression is often modified in various ways; let’s look at the following popular variant:
|I |VI7 |ii7 |V7 |. For example, in G that would be: |G |E#7 |Am7 |D7 |.
The diatonic vi chord is replaced by a non-diatonic secondary dominant chord; this “tonicizes” the ii chord.
In other words, E#7 – Am7 is a V7 – i in A minor, and the progression above can be analysed as:
I – V7/ii – ii7 – V7 – I.

How do we improvise over |G |E#7 |Am7 |D7 | ?
Here are some approaches (that don’t use substitutions!).

1. Improvising in the key
We are basically in G major, with E7 being foreign. So we can use the G major scale throughout, being careful not to play the G note over that E7 chord.
Another possibility, for a more bluesy sound, is to use
– the G blues scale (E pentatonic minor + b5): G Bb C Db D F
– the G Mixolydian scale: G A B C D E F
– a combination of the two

2. Following the changes
We can obviously play phrases using the arpeggios corresponding to the chords.
Or we can associate a scale with each chord.
– On the G chord we can use G major or G Mixolydian

– On the E7 chord we can use A harmonic minor: A B C D E F G#
This makes sense because E7 is the V7 of Am and therefore resolves to Am.

For a more jazzy sound we can also use the E altered scale.
The altered scale is a very common way to improvise over a resolving V7 chord.
To obtain the altered scale:
1) Take the dominant 7th chord (E7) and keep the root (E), the 3 (G#) and the b7 (D)
2) Replace the 5 by b5 (Bb) and #5 (B# = C)
3) Add the b9 (F) and #9 (F## = G)
Result: E F G G# Bb C D

Another definition of the altered scale is: WHWHWWW or (T b2 #2 3 b5 #5 b7)

Yet another way to obtain it is to build the major scale a half step under the root of the E7 chord, and then raise the tonic of that scale by a half step.
In this case: Eb major is Eb F G Ab Bb C D; raising the tonic a half step: E F G Ab Bb C D which can also be written E F G G# Bb C D.
Incidentally, the altered scale is the 7th mode of the melodic minor scale; F melodic minor is F G Ab Bb C D E and the 7th mode of this scale is E F G Ab Bb C D.

– On the Am7 chord we can use A Dorian (A B C D E F# G A), like on any ii7 chord.

– On the D7 chord we can use D Mixolydian (D E F# G A B C) or, again, D altered: D Eb F F# Ab A# C

The choices will depend on the mood, the tempo, the style, and whether you’re having toothache or a bad temper!

For a discussion of the possible improvisation strategies, look here; for a discussion of the chord-scale relationship look there.

I hope you found this interesting and useful.
Regards.

[Mark H]

Cool, thanks J-M! I’ve got my work cut out for me at present with general blues rock improv and theory but used to play a lot of jazz standards. At some point, when I’ve achieved another plateau or two I’ll be wanting to polish-up what I knew about chord melody and integrate it back into all the knowledge I’ve gained in the last two years; your post will be an excellent resource.

[Duffy P]

You stopped the Rhythm changes outline at the close of the A section. The bridge is III7 / III7 / VI7 / VI7 / II7 / II7/ V7 / V7 . Song structure is A A B A. So you would play your progression twice, then the bridge, then the A section again. I’m 99% sure you know this, but just wanted to clarify. Improvising over the back cycling sevenths in the bridge is lots of fun, but requires a slightly different bag of tricks.

[Jean-Michel G]

Thanks for pointing that out; you are absolutely right, of course.
Yes, I know there is more to Rhythm Change than what I outlined, but my subject was the change of the vi7 into a VI7 and what implication that has on the improvisation approach, so I thought I’d just briefly mention Rhythm Change in the intro.

As for the improvisation over the bridge, you are right again. Mixolydian doesn’t work well because those V7 chords are non-functional (they don’t actually resolve). The standard scale approach to those is the Lydian dominant scale: T 2 3 #4 5 6 b7… A different bag it is!

[Jean-Michel G]

It just dawned on me that there is a typo in the original post!
The progression |G |E#7 |Am7 |D7 | should obviously read |G |E7 |Am7 |D7 |.
The VI7 chord in G major is E7, not E#7!

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