Progressions
The jazz blues, in every key
Everyone can play the blues; jazz changes three of its twelve bars and the whole form starts to lean. This page holds both versions — the chart, the fingerings, and a band that loops them in any key you pick.
Twelve bars everyone knows
The blues is the first form a jazz musician learns to play through and the last one they stop playing. Twelve bars, three chords, around and around: four bars on the I, two on the IV, two back on the I, then a four-bar cadence home. Written as scale degrees it belongs to no key in particular, which is the point — the shape is what you memorize, and the key is a choice you make at the gig.
One amendment to that skeleton, and it is the one you will actually hear: bar 2 goes to the IV and comes straight back. That is the quick change, and nearly every jazz musician plays it, so every chart on this page has it — the opening four bars are I, IV, I, I rather than four bars sitting still.
What makes the form a blues rather than a major-key tune is the chord quality: all three chords are dominant sevenths, where the key of F would want an Fmaj7 and a B♭maj7. That permanent flat seventh on chords that are supposed to be stable is the sound itself. In F, the version on this page reads: F7 | B♭7 | F7 | F7 | B♭7 | B♭7 | F7 | D7 | Gm7 | C7 | F7 | C7.
What jazz does to bars 8, 9 and 10
A plain blues ends its chorus by stepping down from above: V7 in bar 9, IV7 in bar 10, home in bar 11. The jazz version rebuilds those bars so that every chord leans on the next one instead.
Bar 8 turns into a VI7 — in F, a D7. That chord is not in the key at all: its F♯ contradicts the F major scale. It is there for one reason, to point at the chord that follows, which is exactly what the secondary dominant does to a pop turnaround. What it points at is bar 9, now a ii7 (Gm7), which walks into the V7 in bar 10 (C7) and lands on the I in bar 11. Bars 9 to 11 are a ii–V–I — the same three-chord engine that drives most of the standard repertoire, dropped into the middle of a blues, with the blues' own twist that it lands on a dominant seventh rather than a major seventh.
Bar 12 stays a V7 in both versions: the turnaround that spits you back into bar 1. Nine of the twelve bars are untouched — which is why a jazz blues and a blues can be played side by side in the same band without a train wreck, and why players who learn one can sit in on the other.
Five grips for a whole chorus
Twelve bars, five different chords, and — voice-led — five drop-2 shapes whose notes all fall between frets 3 and 7. The first eight bars sit in a single four-fret window; from bar 9 the hand shuttles between that window and one two frets higher:
Watch the joins. Going from F7 to B♭7 the F on the D string simply stays put — it is the fifth of B♭7 — while the other three voices step down a semitone or two, which is why the IV chord reads as a shading rather than a departure. Bar 7 into bar 8 costs two semitones in total: one voice up a fret (F to F♯), one down (E♭ to D), two holding — a very small hand movement for a chord that redirects the whole tune. Gm7 to C7 keeps two common tones, G and B♭. And C7 to F7 is the sound of the blues resolving: both guide tones fall a half step and swap jobs, C7's third (E) becoming F7's seventh (E♭), C7's seventh (B♭) becoming F7's third (A).
Every sound on this page is the Drop2 app's own sampled guitar, bass, and drums — from the MuseScore General sound library, used under the MIT license.
Loop it with the band
Twelve bars is long enough that the form has to be felt rather than counted, and that only comes from playing it around. The loop below is the app's Play-Along band — walking bass on every beat, swung ride, hi-hat on 2 and 4 — with the five voicings above comped on top:
Listen for two things. The bass approaches each new chord from a half step below, so the changes arrive as if walked into. And bar 8 is where the tune turns: after seven bars of blues, that D7 announces the last four bars long before they get there.
Hear what jazz changed
Here are the older changes — the plain blues — in the same key, at the same tempo, with the same band and the same voice-led approach. Only bars 8, 9 and 10 differ:
Play one, then the other, and listen only to the last four bars. The plain version steps down and settles; the jazz version takes a running start at home. Neither is a correction of the other — a blues session will ask for both, sometimes in the same chorus — but the jazz changes are what a rhythm section will play behind you when someone counts off a blues at a jazz jam.
Take it around the keys
Pick any key above and the whole page follows: the chart re-spells, the five shapes re-finger to the nearest window, and the band walks the new roots. Start with F — Billie's Bounce, Now's the Time and Straight, No Chaser are all F blues — then B♭ and E♭, the other two keys a horn section pushed the blues into. After that, G and C: the keys a guitarist usually already plays a blues in, now with new bars 8 to 10 in them.
A useful drill: loop one key until you can hear bar 8 coming without counting, then move a fourth up — F, B♭, E♭, A♭ — which is the order the chords themselves keep moving in. The shapes slide; the logic does not.
Where Drop2 comes in
The Drop2 app teaches the vocabulary this page comps with. Learn shows every inversion of all six seventh-chord qualities on three string sets, and Train calls a voicing and listens, through the microphone, to whether you found it. Its curriculum reaches the plain blues before the jazz one, in that order, for the reason this page just demonstrated.
Play-Along, part of Premium, is the band above with the guitar chair empty: it loops the jazz blues in any key while you comp, and it hears whether your chords land. Lines, also part of Premium, runs the same twelve bars for soloing, naming the guide tone to aim at in each bar — including the one bar, bar 8, where the note you want is not in the key.
Free to start, no time limit · Works with acoustic and electric guitar
Next: The minor ii–V–i, in every key →