This week’s Lick of the Week uses a set of substitute changes for the I-VI-ii-V7 progression, a defining feature of Rhythm Changes. Let’s think in terms of C Major for an example. In the key of C, the I-VI-ii-V7 progression is:
Cmaj7 A7 Dmin7 G7
A minor would actually be diatonic, and the vi chord is minor naturally. However, jazz musicians often make this chord dominant instead of minor. This is called “V of ii” in Classical theory, but jazz musicians might just call it a major (or dominant) VI chord.
If you make the VI an A7b9 chord but leave out the root, you are left with a C#dim7 chord! That’s the start of the new substitute I-VI-ii-V7 progression:
Cmaj7 C#dim7 Dmin7 D#dim7
Curiously, the D#dim7 can be thought of as a sub of a sub. The C#dim7 is a direct substitute for the VI chord, A7(b9), in the Key of C. However, the same sub for the V7 chord is a Bdim7, which is not the sub we are using.
However, B7 can actually be a substitute for the V7 chord in the Key of C. It’s not a common sub, but it actually works well. If we make the B7 a B7(b9) and then leave out the root, we are left with D#dim7, which is the sub we are using. The result is a sub of a sub! Both the V7 and the #iidim (or biiidim, whichever way you want to think of it) resolve to the iii chord, Emin, rather nicely.
The resulting I-#1dim-ii-#iidim progression is a substitute for the I-VI-ii-V7 progression. These substitute changes can be used in rhythm changes, but are also a staple of several other tunes, such as Ain’t Misbehavin’, On a Slow Boat to China, and It Could Happen to You.
Now that we now where these substitute chords came from, let’s learn the Lick of the Week!
PDF of Lick of the Week #4 Substitute Rhythm Changes