Progressions

Rhythm changes, in every key

By Oliver Duschka, the developer of Drop2

After the blues, this is the form most likely to be called on you — and the one most likely to be called fast. This page holds its eight bars fingered so your hand stays put, the bridge underneath it at the same tempo, and a band to take both round in any key you pick.

Eight bars, sixteen chords

Gershwin wrote I Got Rhythm in 1930 and jazz kept the chords and threw away the tune. What was left became a form of its own — rhythm changes — and there are hundreds of heads written over it, from Anthropology to Oleo to Rhythm-a-ning. The whole thing is thirty-two bars in AABA: the A section eight bars, played three times, and a bridge of eight in the middle. Gershwin's original was in D♭; the jam session will call it in B♭.

What makes it a different job from the other progressions on this site is density. The ii–V–I gives you a bar to think in. Here the harmony moves twice a bar, so eight bars hold sixteen chords, and the tempo is usually the fastest thing on the setlist. The good news is in the chart: those sixteen chords are only eight different ones, and six of the eight bars are the same four-bar idea coming round again.

Read it that way and the form stops being sixteen things to remember. Bars 1 to 4 are the turnaround played twice, the second pass starting on the iii instead of the I. Bars 7 and 8 are its last two bars again. Everything else — the whole of what makes rhythm changes sound like rhythm changes rather than a long turnaround — happens in bars 5 and 6.

The five chords that cycle

Here are the five chords of those turnaround bars on the top four strings, one drop-2 voicing each — the inversions that sit nearest one another rather than the textbook grips:

Watch the joins, because at this tempo they are the difference between comping and scrambling. From Cm7 to F7 — the ii to the V, which happens three times in eight bars — two voices do not move at all: the C stays put and becomes the fifth of the new chord, and the E♭ stays put and becomes its flat seventh. Of the two that move, one falls a whole step (G to F) and the other falls a half step (B♭ to A). Two fingers, and only just.

Bar 3 is the same event transposed. Going from Dm7 to G7 the four voices make exactly the moves they make in the ii–V — two holding, one falling a whole step, one falling a half — because a minor seventh chord moving to a dominant a fourth above it is the same relationship whatever degree of the key it starts on. Learn the ii–V move and you have learned bar 3 for free. The smallest change in the whole section is the one that follows: coming out of the V7 into the iii, three voices hold and a single voice falls a half step.

Letting each voice take its shortest path like this is voice leading, and the pair doing the leaning in every one of these chords is the third and the seventh: the guide tones. Two honest notes about the cards. The loop has a little more in it than eight grips: in seven of the twelve keys the chain lifts the ii and the V higher for their first pass through bar 2, and in two more it does that to the VI7 instead — the cards show each chord once, in the position the loop settles into. And these are the same four chords as the turnaround page, but mostly not the same fingerings; adding the rest of the form pulls the chain to different inversions in all but two keys.

Why the tonic is written as a sixth

The I chord on the card above probably does not say what you expected. When the voice leading puts the root of a major seventh chord on the top string, the major seventh underneath it sits a half step below a note you are also playing, and the chord is written — and heard — as a sixth instead: the seventh gives way to the sixth degree. It is the same substitution the drop-2 article's third-inversion card carries a note about, and this is the first progression on the site where the chain lands on it. In the two keys where the chain finds the tonic somewhere other than root-on-top, the card says maj7 and nothing is wrong — the name follows the voicing.

The two bars that go somewhere else

Bars 5 and 6 are where the form earns its name. The tonic turns into a dominant seventh, which points it at the IV chord; the IV arrives; and then a diminished chord a half step above the IV walks the bass back home. Three chords, one per half-bar, and they are the only harmony in the section you have not already met:

The move into the IV is one you know from every ii–V–I: going from B♭7 to E♭maj7 the B♭ holds and becomes the fifth, the D holds and becomes the major seventh, the F falls a whole step onto the new root E♭, and the seventh A♭ falls a half step onto G. A dominant chord resolving down a fourth, exactly as the V does at the end of a ii–V–I — the only difference is that here the chord it lands on is the IV rather than the I.

Then the diminished chord, and it is gentler than its name. From E♭maj7 to Edim7 two voices hold still — the G and the B♭ — while the root climbs a half step (E♭ to E) and the major seventh drops a half step onto the diminished chord's own doubly-flattened seventh. Two fingers again. In the bass it is plainer still: the root walks up one fret and then falls back to the tonic for bar 7, which is the whole purpose of the chord. It is a passing note with a harmony built on it.

Every sound on this page is the Drop2 app's own sampled guitar, bass, and drums — from the MuseScore General sound library, used under the MIT license.

Loop it with the band

Walking bass, swung ride, hi-hat on 2 and 4, and the eight voicings above comped on top, two chords to the bar:

A word about the tempo. This loop runs at a speed you can think at, and a jam session will not: rhythm changes is routinely called at 240 and above, which is where players who learned it slowly and players who learned it in one key start to sound different. The fix is not to practise it fast but to practise it until the joins are automatic, and then let the speed arrive. Listen for the bass through bars 5 and 6 — up a half step from the IV, then home — because that chromatic step is the clearest landmark in the form and the easiest place to find yourself again when you get lost.

The bridge

The other eight bars are the simplest thing in jazz to describe and one of the harder ones to play: four dominant seventh chords, two bars each, each one a fourth above the last. No minor chords, no ii–Vs, nothing to resolve until the very end — just a chain of chords all leaning, which finally hands you back to the top for the last A. Same band, same key, same tempo:

Those four roots climb by fourths — each one the same distance above the last — and the fourth of them is the V of the key, so the bridge is one long walk around the circle that arrives back at bar one. That is also why it is a soloist's trap: nothing in it wants to sit still, and there is no tonic to rest on for sixteen beats at a time. The chords here get no cards of their own because the voicings the chain picks for them depend on where in the neck the A section left your hand — pick a key, play the two loops back to back, and watch the strip.

Take it around the keys

Pick any key above and the whole page follows: the chart re-spells, the eight shapes re-finger to the nearest window, the band walks the new roots, and the bridge moves with them. B♭ is where the tune is called, so start there, then E♭ and F — between them those three cover most of what a horn player will count off. C and G after that. The point of doing it in more than one key is not completeness; it is that the shapes stop being positions you memorised and start being the moves described above, which are the same moves everywhere.

A workable drill at this density: play the A section four times without stopping, but comp only on the first chord of each bar, ignoring the second. Half the chords, all of the form. When that is comfortable, put the second chord back in and the hand already knows where it is going. Then add the bridge and play the whole thirty-two.

Where Drop2 comes in

The Drop2 app drills the vocabulary this page comps with. Learn lays out all four inversions of six seventh-chord qualities on three string sets — the diminished chord from bar 6 among them — and Train calls a voicing and listens through the microphone to whether you found it.

Play-Along, part of Premium, is the band above with the guitar chair empty, and it carries both halves of this page as forms of their own: I Got Rhythm (A) and Rhythm Bridge. Running them back to back in one key, at one tempo, is this page turned into a practice session — and the tempo control is where you find out how fast you actually own it. Lines, also part of Premium, plays the same forms for soloing and names the guide tone to aim at in each bar, which on a progression that moves twice a bar is most of the battle.

Next: All the progression pages →