In 1928, George and Ira Gershwin composed the iconic song “I Got Rhythm.” In the years following, the harmonic structure of this timeless classic has become the backbone of countless songs written and/or performed by such varied artists as Charlie Parker, Kenny Rogers, and even the Beatles.
Not only has “I Got Rhythm” been recorded by a plethora of vocalists and instrumentalists, it has also become a measure of a musician’s improvisational skills. A big reason for this is the I-VI-II-V (or III-VI-II-V) progression in the A-sections of the tune. Because these harmonies are in so many standard tunes (jazz, pop, rock, gospel, and country), if you can improvise over “Rhythm Changes,” you can improvise over a lot of other tunes in a variety of styles.
The structure of “Rhythm Changes” is the 32-bar AABA form, with each section consisting of eight measures. The A-sections contain the I-VI-II-V progression. The B-section consists of dominant seventh chords starting on the III7, moving in a cycle of fourths. To hone your skills, isolate the sections, and practice playing on each of them before putting the parts back together. Then, you’ll be ready to use these devices on dozens of tunes!
Ex. 1. The I-VI-II-V progression in the key of Bb. This progression is repeated in the first four measures of “I Got Rhythm” in the A sections. Although the original was in the key of Db (as were many songs composed in that era), the most common key for “Rhythm Changes” these days is Bb.
Ex. 2. The melody of “I Got Rhythm” is drawn from the major pentatonic scale (1, 2, 3, 5, 6). The bulk of the melody in the A-sections uses four of the five notes of that scale. This right hand improvisation uses the Bb major pentatonic scale, along with the “blue” notes b3 and b7. The b7 is introduced in measure 5, to reinforce the modulation to the IV chord, a pivotal harmonic movement in “Rhythm Changes.” Notice the subtle difference between the first and second endings — a good way of keeping your place in this AABA form. Click for audio.
Ex. 3. The first half of the B-section starts on the III7 and moves up the cycle of fourths. Left hand voicings consist of guide tones (thirds and sevenths) and roots. The right hand is using the dominant diminished scale, always a good choice for use on dominant sevenths. Click for audio.
Ex. 4. In the second half of the bridge, we’re preceding the dominant seventh chords by minor seventh chords (often called “II-V’ing”). This gives us more chords to play on, and adds some extra movement, while retaining the underlying harmonic intent. The right hand lines outline the minor seventh chords with some added chromatic tones. Notice that the seventh of the minor chord resolves to the third of the dominant seventh chord. Click for audio.
Ex. 5. The final A-section. By outlining the chords in the right hand, the tune almost plays itself. Along with a few choice chromatic tones, you can weave an eighth-note improvisation over the moving changes quite nicely. The diminished chords are common substitutions for the dominant sevenths in the first two measures. For dramatic effect, we end on the tritone substitution of E7#11. Click for audio.
Jazz pianist, composer, and longtime Keyboard contributor Andy LaVerne has played and recorded with such renowned artists as Frank Sinatra, Stan Getz, and Chick Corea. A professor of jazz piano at the Hartt School of Music at the University of Hartford, his latest CD is Live at the Kitano, Vol. 1. Visit him at andylaverne.com.