TheRhythm changes is a common 32-barjazzchord progression derived fromGeorge Gershwin's "I Got Rhythm". The progression is inAABA form, with each A section based on repetitions of the ubiquitousI–vi–ii–V sequence (or variants such as iii–vi–ii–V), and the B section using acircle of fifths sequence based on III7–VI7–II7–V7, a progression which is sometimes givenpassing chords.
This pattern, "one of the most common vehicles for improvisation,"[2] forms the basis of countless (usually uptempo) jazzcompositions and was popular withswing-era andbebop musicians. For example, it is the basis ofDuke Ellington's "Cotton Tail"[3] as well asCharlie Christian's "Seven Come Eleven,"[4]Dizzy Gillespie's "Salt Peanuts,"[4] andThelonious Monk's "Rhythm-a-Ning".[4] The earliest known use of rhythm changes was bySidney Bechet in his September 15, 1932[5] recording of "Shag" (two years after the first performance of "I Got Rhythm" on Broadway) with his "New Orleans Feetwarmers" group.[6]
In pop culture, "Meet the Flintstones", (c. 1960, Curtin/Hanna/Barbera) is based on the rhythm changes, thereby being acontrafact of "I Got Rhythm".
This progression's endurance in popularity is largely due to its extensive use by earlybebop musicians. The chord changes began to be used in the 1930s, became common in the '40s and '50s, and are now ubiquitous.[7] First, "I Got Rhythm" was by then already a popularjazz standard. Second, by listening to the song and writing a new melody over its chord changes, thereby creating a composition of a type now known as acontrafact, a jazz musician could claimcopyright to the new melody rather than acknowledge Gershwin's inspiration and payroyalties to Gershwin's estate. Third, using a stock, well-known progression for new melodies made it easier to perform a song atjam sessions, shows, and recordings because the bandleader could tell new musicians that the song uses rhythm changes and note any modifications andchord substitutions.
For contemporary musicians, mastery of the12-bar blues and rhythm changes chord progressions are "critical elements for building a jazzrepertoire".[8]
The rhythm changes is a32-bar AABAform with each section consisting of eight bars, and four 8-barsections.[9] Inroman numeral shorthand, the original chords used in the A section are:
| I vi | ii V | I vi | ii V |
a 2-barphrase,I−vi−ii−V (often modified to I–VI–ii–V), played twice,[10] followed by a 4-bar phrase
| I I7 | IV iv | I V | I |
In ajazz band, these chord changes are usually played in thekey of B♭[7] with variouschord substitutions. Here is a typical form for the A section with various common substitutions, including bVII7 in place of the minor iv chord; the addition of aii–V progression (Fm7–B♭7) that brieflytonicizes the IV chord, E♭; using iii in place of I in bar 7 (the end of the first A section); and using a ii-V-I in place of I-V-I in bars 15 and 16 (the end of the second A section):
The "bridge" consists of a series ofdominant seventh chords (III7–VI7–II7–V7) that follow thecircle of fourths (ragtime progression), sustained for two bars each, greatly slowing theharmonic rhythm as a contrast with the A sections. This is known as theSears Roebuck bridge, named afterSears, Roebuck and Co.[11]
The B section is followed by a final A section
Variant versions of changes are common due to the popularity of adding interest withchord substitutions,passing chords, and changes ofchord quality. Bebop players, for instance, would often superimpose series of ii–V progressions (passing sequences ofminor seventh anddominant seventh chords) or other substitutions for interesting or in order to discourage less experienced musicians from "sitting in" on the bandstand. The opening I chord wasB♭6 in Gershwin's original, but beboppers changed it toB♭M7 orB♭7. For instance, the B section may appear as follows:[12]
An even more adventurous bebop-style substitution is to convert C7 | C7 | F7 | F7 to Gm7 | C7 | Cm7 | F7, and then further develop this substitution by changing this to Am7 D7 | Gm7 C7 | Dm7 G7 | Cm7 F7.
The following is a partial list of songs based on the rhythm changes:
| Title | Artist | Year | Source |
|---|---|---|---|
| Anthropology | Charlie Parker/Dizzy Gillespie | 1946 | [7] |
| Cotton Tail | Duke Ellington | 1940 | [3][4] |
| Crazeology | Benny Harris | [13] | |
| Dexterity | Charlie Parker | [7] | |
| The Eternal Triangle | Sonny Stitt | 1957 | [13] |
| Fungii Mama | Blue Mitchell | 1964 | |
| Gee (solo section) | Gustavo Assis-Brasil | [14] | |
| Lester Leaps In | Lester Young | 1939 | [6] |
| Moose the Mooche | Charlie Parker | 1946 | [6] |
| Oleo | Sonny Rollins | 1954 | [7] |
| Passport | Charlie Parker | [6] | |
| O Latido do cachorro | David Feldman | ||
| Rhythm-A-Ning | Thelonious Monk | 1957 | [6] |
| The Serpent's Tooth | Miles Davis | [13] | |
| Steeplechase | Charlie Parker | [7] | |
| Straighten Up and Fly Right | Nat King Cole | 1943 | [6] |
| The Theme | Miles Davis | 1955 | [13] |
| Tiptoe | Thad Jones | [6] |
The component A and B sections of rhythm changes were also sometimes used for other tunes. For instance,Charlie Parker's "Scrapple from the Apple" andJuan Tizol's "Perdido" both use a different progression for the A section while using the rhythm changes bridge.[15] "Scrapple from the Apple" uses the chord changes of "Honeysuckle Rose" for the A section but replaces the B section with III7–VI7–II7–V7.
Other tunes use the A section of "Rhythm" but have a different bridge.Tadd Dameron's "Good Bait" uses the A section of the Rhythm changes but a different progression for the bridge.[16]
As well found in Olav Jullums composition 'Bedroom Leaves.'
