Beyond Blues: “Rhythm” Changes and the Blues

One of the most daunting aspects of taking your blues playing to the next level is turning up to a jam night and finding out that the players lean toward the jazzier side of the blues. For the last few years, this column has sought to shed light on relevant aspects of the jazz idiom by introducing you to intriguing scales and soloing concepts you can use in a blues context. But what happens if the context is jazz? There’s a common pool of songs that jazz musicians pull from, and some of those songs can be classified as a contrafact. A contrafact is a composition that’s based on an established set of chord changes. The practice became common in the bebop era when musicians wanted to improve their chops by playing over chord progressions they were extremely familiar with. They would then write new melodies to some of their favorites songs.

It wouldn’t be a stretch to consider the blues progression as a contrafact, since so many tunes use those changes. Other common jazz tunes that have served as inspiration for countless contrafacts are “Cherokee,” “All the Things You Are,” “Giant Steps,” and of course “I Got Rhythm.” There are so many tunes based on that Gershwin classic that the progression has become known simply as “rhythm” changes.

The progression consists of two basic sections, which are referred to as A and B. The A section is more intimidating because the harmonic rhythm is a bit quicker with two chords per measure—often played at a brisk tempo. By comparison, the B section is much easier with each chord lasting two measures each. Since the introduction of this progression, many jazz musicians have added various substitutions, but check out the chart below for a generally accepted version and the basis for our examples.

While the A section does use some substitutions, it can be thought of as I–VI–IIm–V. In the key of Bb that would be Bbmaj7–G7–Cm7–F7. Ex. 1 shows you how a jazz guitarist might approach this progression. There are a lot of notes that outline the changes here, but I’m playing a Bb triad (Bb–D–F) over the Bb, a G7b9 arpeggio (G­–B–D–F–Ab) over the G7, and just connecting chord tones over the Cm7 and F7 chords. The principle idea is very simple, but executing it on the fly and at speed will feel nearly impossible to someone with a background exclusively in blues.

Click here for Ex. 1

Ex. 2 is more of the same, but this time we move higher up the neck. The vocabulary is very similar though, sticking closely to the chords and using diminished arpeggios to imply 7b9 sounds.

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It’s also possible to play convincingly over rhythm changes using more of a blues feel. In Ex. 3, we are using a lot of the Bb blues scale (Bb–Db–Eb–E–F–Ab). While a purist might argue these notes don’t fit the chords, the golden rule applies: If it sounds good, it is. If you like it, keep playing!

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Ex. 4 dials it back a little with bigger bends and slides. I’m even throwing in a country-inspired bend going into the third measure. We stick with the Bb minor pentatonic (Bb–Db–Eb–F–Ab) with hints of the blues scale and b5 (E).

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Ex. 5 uses the concept of tension and release. I’m thinking in major for the first measure, then minor in the second, then back to major, and again back to minor. This doesn’t outline the changes too tightly, but does give a super bluesy sound. I added the double-stops in the second measure for a bit of spice.

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We are also using the major/minor theme in Ex. 6, but this time we’re moving between Bb major pentatonic (Bb–C–D–F–G) and Bb minor pentatonic (Bb–Db–Eb–F–Ab). The triplet run can be a technical challenge, so take it slow.

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The B section presents its own challenges. The pace of the changes has decreased, but this slow speed means that playing sounds that don’t really fit the changes will stand out. In Ex. 7 the basic concept is to work a simple idea through a series of dominant 7 chords. We’ll start with the “E” shape of the CAGED system and move it up and down the neck to outline D7, G7, C7, and F7, respectively.

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Ex. 8 takes that basic idea, but focuses more tightly on one area of the neck. Over the D7, we’re using more dominant-sounding vocabulary around the “E” shape, which resolves to the “A” shape (also at the 10th fret) for the G7 chord. This concept is then shifted down two frets to outline the C7 and F7. As with the previous example, this idea resolves to a gritty Bb minor pentatonic phrase.

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We channel a little more blues vocabulary with some Clapton and SRV influences in Ex. 9. Over the D7 we’re playing obvious D minor pentatonic (D–F–G–A–C) vibes before moving to a figure based around the G major pentatonic scale (G–A–B–D–E). We then move to C Mixolydian over the C7 (C–D–E–F–G–A–Bb), and F Mixolydian (F–G–A–Bb–C–D–Eb) over the F7 before resolving to some Bb blues moves.

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Finally, no bebop-influenced column would be complete without some complex double-time ideas (Ex. 10). The line is simple, just played at twice the speed. For the most part it’s based on the Mixolydian scale with an added b3. We spice things up with some C Lydian Dominant (C–D–E–F#–G–A–Bb) on the C7, and some F Super Locrian on the F7 (F–Gb–Ab–A–B–Db–Eb) before resolving to the Bbmaj7.

That one isn’t for the faint of heart, but all good fun!

Click here for Ex. 10

Finally, here’s a full chorus of rhythm changes for you to practice over and explore some of these ideas.