Think of these examples as harmonic plug-ins—hip grips you can insert at specific points in the 12-bar form to add drama to the music. To help you compare the various moves and voicings, we’ll stay in the key of G throughout the lesson. Once you’ve assimilated the ideas as presented here, your next step will be to rework the moves in other keys, mixing and matching voicings to create custom variations. The first measure of each example is numbered, so you’ll know exactly where to place it within the 12-bar scheme. If you can hit the I-IV-V changes in a standard blues, you’re ready to go.
Strong chord progressions generate forward motion, and one way to create this momentum is to embed a chromatic line within the changes. Ex. 1, a I-IV move starting on bar 4, illustrates the process with a three-note
chromatic line in the top voice (E, D#, D) that pulls your ear into C9. With its altered tone (D#), the bristly G7#5 sets up two beats of dissonance that’s released on the downbeat of bar 5. If you look closely at the G7#5-C9 change, you’ll see that as the chord root jumps up a perfect fourth (G to C), the other three notes shift down by a half-step: F-B-D# drops to E-Bb-D. Such contrary motion tightens up a chord change.
Another I-IV move, Ex. 2 takes the idea of chromatic stepping-stones a notch further. For starters, we have another three-note descending chromatic line in the top voice (A, Ab, G). But there’s more: Lurking in the Db9 passing chord are two tones (Eb and Ab) that generate spiky dissonance against the prevailing I chord. To cap things off, all four notes drop by a half-step as we enter the IV chord, heightening the sense of tension and release.
In Ex. 3, we use chromatics to ascend from the I (bar 8) to the V. Check it out: A three-note chromatic line in the top voice (G, Ab, A) connects G13 to D9; the Eb and Ab appear again to rub against the prevailing I; and all four voices slide by a half-step across the bar line.
A V-IV-I cadence (bar 11), Ex. 4 is packed with goodies, including a three-note descending chromatic line in the top voice (D, Db, C), a chromatic line in the bottom voice that crawls down and up (C, B, Bb, B), contrary motion in the top and bottom voices of the last two changes (Bb, B against Eb, D), plus lots of half-step shifting between the chords. The clangy D9 grip is great for cutting through a slammin’ funk groove.
You can create attention-grabbing tension and release by wedging a diminished chord into standard I-IV-V blues changes. In Ex. 5, we’re making the transition from G7 (I) to D9 (V), by way of Gdim7. Starting in bar 8, this phrase features a pair of chromatic lines that descend in parallel on strings one and three (B, Bb, A and D, Db, C). The diminished flavor lasts only two beats—a quick turnstile linking the two main chords.
A related move is a IV-#IVdim-I shift, which you can hear in Ex. 6. It’s a foolproof way to perk up the harmony in the middle of a 12-bar blues. This time the diminished harmony lasts for a full measure, which gives you the opportunity to try a cool trick: Diminished voicings repeat themselves every three frets, so after playing the C#dim7 grip in the sixth position for two beats, you can scoot the same grip up to the ninth or down to the third position to finish the measure. You can fret G13 as written, or play a I that’s closer to the second C#dim7. If you slide up the fretboard, use the G9 voicing from Examples 2 and 3. If you trek down the neck for the second C#dim7, try Ex. 1’s G13 grip.
Inserting IIm-V Changes
The IIm-V-I progression is as central to jazz as the I-IV-V is to blues. Although some modern jazz composers strive to avoid the ubiquitous IIm-V chords, this progression forms the backbone of swing, bebop, and other classic styles. Why? The IIm-V change is a ruthlessly efficient way to approach a key’s home base—the tonic or I chord. There are two reasons for this. First, the IIm-V-I move nails all seven tones of a given key in just three chords. But most importantly, the root motion for this progression follows a sequence of fourths—the strongest of all root motion. (See “The Wonder Wheel.”)
By inserting a IIm-V change into the concluding measure of a 12-bar blues progression, we expand our harmonic options with an extra chord—the IIm. Try Ex. 7, in which Am9 precedes the traditional D9. The way these chords are voiced, we don’t need to play D9’s root to hear the rock-solid IIm-V-I cadence.
Ex. 8 puts another twist on this idea. Here, the Am11-D7b5-G9 grips yield a chromatically descending line in the bottom voice—A, Ab, G. This chromatic bass is another effective way to approach the I chord from bar 12. The common tone—D—riding in the top voice acts as sonic glue to hold the harmony together.
Backing up to bar 11—normally G7’s turf—we can run a chromatic line in the bottom voice that climbs up and down, courtesy of a diminished passing chord. Listen to Ex. 9, and examine what’s happening on the sixth string. Adding the IIm in bar 12 gives us an opportunity to advance on it in bar 11 using a diminished chord, in this case a bIIdim. As you start working with more complex enhancements to the standard I-IV-V blues changes, it’s helpful to play through the entire progression from the top, so you can hear the “plug-in” in context.
With a little ingenuity, you can spin each of this lesson’s examples into several new phrases that follow the same basic chord pattern, but use different voicings and fretboard positions. Ex. 10 illustrates the process: Compared to the previous example, we’re playing higher up the neck and using different grips (i.e. G13 instead of G7, and D9 instead of D7b5), but the essential harmonic motion—and location within the progression—is identical. This is why it pays to study the principles behind any harmonic moves. Once you unlock or decode a concept, you’re free to recycle it in other locales and keys.
The Deceptive IIm-V
We’re not done with the IIm-V change. Using a bit of harmonic wizardry, we’ll create a deceptive cadence to build momentum heading into the IV chord (bar 5). Here’s the four-step process:
- Identify the root of bar 5’s IV7 chord.
- Treat this note as a momentary tonic, or I.
- In bar 4, play the IIm-V change that resolves to the momentary tonic.
- When you reach bar 5, the target chord reverts to its role as the IV in a 12-bar blues.
Ex. 11 puts the technique to work in our G blues. The IV, C9, yields a C root. Looking backward to bar 4, we see that the Dm9 and G7#5 chords form a IIm-V cadence pointing at C. Rather than stopping at C9, however, we play the chord as a IV and keep trucking toward the real tonic—G. When you want to concoct this type of deceptive cadence on the fly, you can think of the three chords as forming a Vm-I-IV progression.
Hey, why limit ourselves to a single IIm-V move? A double whammy, Ex. 12 contains a pair of IIm-V cadences. This example ends on G7, the I, which launches bar 1 of a fresh 12-bar cycle. Preceding G7 is the standard IIm-V move that snaps into bar 12 (we first encountered this trick in Ex. 8). So we now have an Am7-D7b9-G7 cadence—so far, so good. If we treat the root of Am7 as a momentary I, we can precede it with a IIm-V cadence. This thinking yields bar 11’s Bm7-E7b9 change.
Taken as a whole, the Bm7-E7b9-Am7-D7b9 progression forms an extended ramp into G7, topped with a snazzy five-note chromatic line (F#, F, E, Eb, D). The key here, as with most harmonic substitutions, is to first look ahead to the destination, and then reverse-engineer the harmonic path from this arrival point. After you grasp the recurring IIm-V structure in this progression, you can convert the two cadences into a single formula of IIIm-VI-IIm-V-I, which some players find easier to remember on the bandstand or in the studio.
One of the most potent techniques available for hot-rodding blues progressions is called backcycling. There are several ways to understand the mechanics, but a great place to start is with the VIm-IIm-V-I progression. In the basic version of this cadence, the chord roots are based on the 6th, 2nd, 5th, and 1st tones of the key’s major scale, and then harmonized diatonically. This process yields two minor chords—the VIm and IIm. Ex. 13 boasts a classic VIm-IIm-V-I turnaround that starts in the middle of bar 11. The only non-diatonic notes are appended to the V. These altered tones—the #9 and b9—increase tension going into the I.
Let’s look at these chords another way: If you track the turnaround’s root motion (E, A, D, G) on the cycle chart, you’ll see that it follows four consecutive counterclockwise “clicks.” In other words, starting on E, we’re ratcheting backward—backcycling—in fourths until we reach our a final destination of G. This root motion is so strong you needn’t stick to diatonic harmony when launching a turnaround from within bar 11, as evidenced by Ex. 14 and its “all dominant 7” backcycling move. Starting with E7, notice how the intervals on the third and fourth strings descend chromatically from one chord to the next, even as the roots hop between the fifth and sixth strings. You’ll often hear this dominant backcycling maneuver in jump swing.
Now that we’ve got a series of dominant 7s in place, we can throw down a few tritone substitutions. (To understand the theory behind this technique, see “Tritone Twins.”) In Ex. 15, we replace the VI and V dominant chords with dominant 7s whose roots are a diminished fifth (b5) away. Instead of E7 (VI), play Bb7; instead of D7 (V), play Ab7. The intervals on the third and fourth strings remain the same as in the previous example, but now the roots descend chromatically along the sixth string.
Using tritone substitutions, you can reshape progressions you already know. For example, take the IIIm-VI-IIm-V-I (or double IIm-V) sequence we encountered earlier in Ex. 12. Replace the VI and V chords with their tritone twins, and you get Ex. 16—a hip phrase with three descending chromatic lines (strings six, four, and two) and alternating minor/dominant textures. Sweet!