I Got Rhythm
The most common chord progression found in Jazz is the 12 Bar Blues. The second most common chord progression is Rhythm Changes.
Rhythm Changes are a chord progression based on the song I Got Rhythm by George Gershwin.
I Got Rhythm technical details:
- The original song is 34 bars long (32 bars AABA + 2 bar outro)
- Rhythm Changes ignores the outro and just keeps the first 32 bars
- It has an AABA form (with standard 8 bar sections)
- It is originally in the key of B♭ Major
Now, it’s important to understand that there is no single Rhythm Changes chord progression. Rather, it is a number of different progressions all derived from the original I Got Rhythm progression. This is similar to the 12 Bar Blues – which also has a basic structure and then hundreds of variations.
So let’s break it down and look at each section individually, beginning with Section A.
Section A
Base Progression
At it’s absolute most minimalistic and simplest, Section A is just a I-V-I-V progression for 8 bars.
| Bar | 1 | 2 | 3 | 4 |
| Base Prog | B♭6 | F7 | B♭6 | F7 |
| Bar | 5 | 6 | 7 | 8 |
| Base Prog | B♭6 | F7 | B♭6 | F7 |
Simplified Rhythm Changes Progression
To make this ‘base’ chord progression a little more interesting we can insert some chord substitutions. Below are two widely used chord substitutions for the B♭6 and F7 chords.
| Chord | Notes | Substitute Chord | Notes | Substitution type |
|---|---|---|---|---|
| B♭6 | B♭ D F G | Gm7 | G B♭ D F | Median Note |
| F7 | F A C E♭ | Cm7 | C E♭ G B♭ | II-V |
So employing these chord substitutions, we can turn a I-V progression into a I-VI-II-V Progression, repeated for the whole 8 bars.
At it’s heart, Rhythm Changes are just a I-VI-II-V Progression.
| Bar | 1 | 2 | 3 | 4 |
| Simplified Prog | B♭6 - Gm7 | Cm7 - F7 | B♭6 - Gm7 | Cm7 - F7 |
| Base Prog | B♭6 | F7 | B♭6 | F7 |
| Bar | 5 | 6 | 7 | 8 |
| Simplified Prog | B♭6 - Gm7 | Cm7 - F7 | B♭6 - Gm7 | Cm7 - F7 |
| Base Prog | B♭6 | F7 | B♭6 | F7 |
Songs that use this simplified chord progression are:
- Don’t be that Way
- Blue Moon
- Lester Leaps In
Original Rhythm Changes
This ‘simplified’ chord progression can be further modified into the actual chord progression used in I Got Rhythm. We leave all the above bars the same except bars 5 & 6, where we substitute a few new chords as outlined below. These new chords are Borrowed Chords – see the lesson on Modal Interchange for more details.
| Bar | 1 | 2 | 3 | 4 |
| Original Prog | B♭6 - Gm7 | Cm7 - F7 | B♭6 - Gm7 | Cm7 - F7 |
| Simplified Prog | B♭6 - Gm7 | Cm7 - F7 | B♭6 - Gm7 | Cm7 - F7 |
| Base Prog | B♭6 | F7 | B♭6 | F7 |
| Bar | 5 | 6 | 7 | 8 |
| Original Prog | B♭6 - B♭7 | E♭6 - E♭m7 | B♭6 - Gm7 | Cm7 - F7 |
| Simplified Prog | B♭6 - Gm7 | Cm7 - F7 | B♭6 - Gm7 | Cm7 - F7 |
| Base Prog | B♭6 | F7 | B♭6 | F7 |
This is now the original I Got Rhythm chord progression. This is used in songs like:
- I Got Rhythm (obviously)
- Daphne
- Cotton Tail
- Anthropology
- Oleo
Although, this technically isn’t true. Many (most/all) of the above songs don’t actually use this EXACT chord progression. But rather add even further chord substitutions on top of this ‘original’ chord progression. And so…
Further Chord Substitutions for Rhythm Changes
Because Rhythm Changes are so simple, they are also very versatile and flexible. They allow for many possible substitutions and variations. Below is a selection of possible variations on I Got Rhythm which would all still be classified as Rhythm Changes. You can mix and match any combination of bars.
| Bar | 1 | 2 | 3 | 4 |
| Original | B♭6 - Gm7 | Cm7 - F7 | B♭6 - Gm7 | Cm7 - F7 |
| II-V | B♭6 - G7 | Cm7 - F7 | Dm7 - G7 | Cm7 - F7 |
| m=V7 | B♭6 - G7 | C7 - F7 | B♭6 - G7 | C7 - F7 |
| Ascend bass | B♭6 - Bo | C7 - C#o | Dm7 - G7 | Cm7 - F7 |
| Co5th | F#7 - B7 | E7 - A7 | D7 - G7 | C7 - F7 |
| Descend | B♭7 - A♭7 | G♭7 - F7 | B♭7 - A♭7 | G♭7 - F7 |
| Bar | 5 | 6 | 7 | 8 |
| Original | B♭6 - B♭7 | E♭6 - E♭m7 | B♭6 - Gm7 | Cm7 - F7 |
| II-V | Fm7 - B♭7 | E♭7 - A♭7 | Dm7 - G7 | Cm7 - F7 |
| Other | B♭7 | E♭6 - E♭m7 | Dm7 - Gm7 | Cm7 - F7 |
| Ascend bass | B♭6 - B♭7/D | E♭6 - Eo | B♭6/F - Gm7 | Cm7 - F7 |
| Descend bass | B♭6 - B♭7/A♭ | E♭6/G - A♭7/G♭ | B♭6/F - Gm7/D | Cm7 - F7 |
| Outro #1 | - | - | B♭6 - F7 | B♭6 |
| Outro #2 | - | - | Cm7 - F7 | B♭6 |
All of these are possible versions of Rhythm Changes. Now lets move onto Section B.
Section B
Section B of Rhythm Changes is easy. It has one single goal or objective.
Objective: Get to F7 (or B7, the tritone substitution) on the last bar of Section B
This is the V7 of B♭, so will create a V-I cadence when we move on to the final A Section (which begins on the B♭6).
This is done by going through a Dominant Circle Progression. The original I Got Rhythm starts on D7 and moves through G7, C7 and then to F7 – for 2 bars each. Below is a selection of possible alternatives.
| Bar | 17 | 18 | 19 | 20 |
| Original | D7 | D7 | G7 | G7 |
| II-V | Am7 | D7 | Dm7 | G7 |
| Tritone Sub | D7 | D7 | D♭7 | D♭7 |
| Don’t be that way | A7 | A7 | D7 | D7 |
| Straight Ahead | E7 | E7 | E♭7 | E♭7 |
| Bar | 21 | 22 | 23 | 24 |
| Original | C7 | C7 | F7 | F7 |
| II-V | Gm7 | C7 | Cm7 | F7 |
| Tritone Sub | C7 | C7 | B7 | B7 |
| Don’t be that way | G7 | G7 | C7 | F7 |
| Straight Ahead | D7 | D♭7 | C7 | B7 |
And once we get to F7 at the end of Section B, we go back and play the final Section A one last time. And you’re done.
Other Variations
Other variations on Rhythm Changes involve moving bits of the chord progression around to other parts of the song. For example, Section A of Thelonious Monk’s Rhythm-A-Ning is shown below. Notice bars 1 & 2 are the same as bars 5 & 6.
| Bar | 1 | 2 | 3 | 4 |
| Original Prog | B♭6 - Gm7 | Cm7 - F7 | B♭6 - Gm7 | Cm7 - F7 |
| Rhythm-A-Ning | B♭6 - B♭7 | E♭7 - Eo7 | B♭6 - Gm7 | Cm7 - F7 |
| Bar | 5 | 6 | 7 | 8 |
| Original Prog | B♭6 - B♭7 | E♭6 - E♭m7 | B♭6 - Gm7 | Cm7 - F7 |
| Rhythm-A-Ning | B♭6 - B♭7 | E♭7 - Eo7 | B♭6 - Gm7 | Cm7 - F7 |
Have a Listen to
The below songs all use Rhythm Changes. Check them out.
- Anthropology ~ Charlie Parker
- Moose the Mooche ~ Parker
- Steeplechase ~ Parker
- Dexterity ~ Parker
- Cotton Tail ~ Duke Ellington
- Fingers ~ Thad Jones
- Little Pixie II ~ Thad Jones
- Daphne ~ Django Reinhardt
- Double Whiskey ~ Django Reinhardt
- Don’t be That Way ~ Benny Goodman
- Lester Leaps In ~ Lester Young
- Oleo ~ Sonny Rollins
- Rhythm-A-Ning ~ Thelonious Monk
- The Eternal Triangle ~ Sonny Stitt
- Straighten Up and Fly Right ~ Nat King Cole
- Tip Toe ~ Thad Jones
- The Theme ~ Miles Davis
- The Serpent’s Tooth ~ Miles Davis
- Crazeology ~ Benny Harris
- Five Guys Named Moe ~ Louis Jordan
- Blue Moon ~ Rodgers & Hart
- Salt Peanuts ~ Dizzy Gillespie
- Shaw Nuff ~ Dizzy Gillespie
- Christopher Columbus ~ Chu Berry
Conclusion
At it’s simplest, Rhythm Changes are:
Section A = Repeating I-VI-II-V
Section B = Dominant Circle Progression ending on the Dominant of ultimate key (F7 in the key of B♭ Major)
With a heap of chord substitutions.
It’s also worth noting that many songs use just Section A of Rhythm Changes and then a different Section B. While many other songs use just Section B of Rhythm Changes and then a different Section A. So as you can see, Rhythm Changes are very flexible.
And that, in a nutshell, is Rhythm Changes. Make sure you practice comping and improvising over them (in every key). Because they are as important to Jazz as the 12 Bar Blues. Every Jam Session should include at least one go round Rhythm Changes.