By Peter Spitzer - Jazz Author, Musician, and Instructor The term Rhythm changes refers to a chord progression that derives from George Gershwins song I Got Rhythm (1930). The song became quite popular, and within a few years jazz musicians began to borrow its chord structure for some of their own compositions. However, it should be noted that Rhythm changes evolved into a chord progression that was not exactly Gershwins. As was often the case with other songs, jazz musicians streamlined the progression, reducing it to a simpler, more improv-friendly harmonic framework. Songs employing Rhythm changes became a common staple at jam sessions, and are today still an essential part of jazz repertoire. The chord progression is a must-know for any aspiring jazz player. Rhythm changes are almost always played in the key of Bb (Gershwins original key). As played by contemporary musicians, the chord structure is more or less as shown here: Bb: I │ V of II │ II │ V │ I │ V of II │ II │ V │ ║ Bb6 │ G7b9 │ Cm7 │ F7 │ Bb6 │ G7b9 │ Cm7 │ F7 │ - - I │ V of IV │ IV │ IVm6 │ I │ V of II │ II │ V │ │ Bb │ Bb7 │ Eb │ Ebm6 │ Bb6 │ G7b9 │ Cm7 │ F7 ║ - - I │ V of II │ II │ V │ I │ V of II │ II │ V │ ║ Bb6 │ G7b9 │ Cm7 │ F7 │ Bb6 │ G7b9 │ Cm7 │ F7 │ - - I │ V of IV │ IV │ IVm6 │ I │ V │ - I │ │ Bb │ Bb7 │ Eb │ Ebm6 │ Bb6 │ F7 │ - Bb6 ║ - G: V │ - C: V │ - │ ║ D7 │ D7 │ G7 │ G7 │ - F: V │ - Bb: V │ - │ │ C7 │ C7 │ F7 │ F7 ║ - Bb: I │ V of II │ II │ V │ I │ V of II │ II │ V │ ║ Bb6 │ G7b9 │ Cm7 │ F7 │ Bb6 │ G7b9 │ Cm7 │ F7 │ - - I │ V of IV │ IV │ IVm6 │ I │ V │ - I │ │ Bb │ Bb7 │ Eb │ Ebm6 │ Bb6 │ F7 │ - Bb6 ║ - The chord sequence may be broken down this way: Measures 1-2 and 3-4: These are two 2-bar turnarounds.

m.5: The I chord is made dominant, turning it into a V of IV.

m.6: Resolution to IV, followed by IVm6.

mm.7-8: Another turnaround, setting up the second A section.

mm.9-16: This is the second A section, an exact repeat of the first A except for the I V I cadence in mm. 15-16.

mm.16-24: Circle of dominants, two bars per chord. Each dominant chord resolves into the next, leading to mm. 23-24, which is the V of the original key, setting up the last A section.

mm.25-32: An exact repeat of the second A section. Gershwins I Got Rhythm also added a two-bar tag as part of the melody and the harmonic structure; the tag is omitted in most other Rhythm tunes. Variations As with blues changes, musicians often apply certain standard variations to the basic chord progression, either by previous arrangement or on the spur of the moment. Here are some of these variations: Turnarounds in the A sections may include substitutions. For example, | Dm7 G7b9 | Cm7 F7b9 | , or | Dm7 Db7 | Cm7 B7 | m.5 might be: | Fm7 Bb7 |

m.6 might be: | Eb6 Edim7 |

In the bridge, each dominant chord might be prepared with its respective II chord: || Am7 | D7 | Dm7 | G7 | Gm7 | C7 | Cm7 | F7 ||



or tritone substitutions might be used in mm. 19-20 and mm. 23-24: || D7 | D7 | Db7 | Db7 | C7 | C7 | B7 | B7 ||

Tunes using Rhythm Changes Some of the better-known tunes that employ Rhythm changes are: Anthropology, Dexterity, Oleo, Steeplechase, Cottontail, Moose the Mooche, Lester Leaps In, Shaw Nuff, The Theme (Miles Davis), the theme to The Flintstones, Allens Alley, and Rhythm-A-Ning. Scrapple From The Apple uses a Rhythm bridge with a Honeysuckle Rose A section; Good Bait has a Rhythm A section, with a bridge that uses the same chords, transposed up a fourth. The majority of these tunes date from the bebop years (1940s to early 1950s).

For more on Rhythm changes, see Peter Spitzers Jazz Theory Handbook. Available at Amazon... Peter Spitzer

Mel Bay Jazz Theory Handbook

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(Jazz Theory Handbook is a great jazz theory resource for beginners and established musicians. Click the graphic to see our review.) (Jazzis a great jazz theory resource for beginners and established musicians. Click the graphic to see our review.)