The 12-bar blues is a 12-bar chord form built on the I, IV and V chords: F7, B flat 7 and C7 in the key of F. F7 holds bars 1 to 4, B flat 7 bars 5 and 6, F7 bars 7 and 8, then C7, B flat 7 and F7, with a C7 at the very end.
When I started playing guitar, I was kind of stuck playing all these pentatonic ideas. I thought they were cool, but I always felt like I was playing the same things. So in this lesson, with bassist Adam Neely, we take the good old-fashioned 12-bar blues and go through five levels where our harmonic vocabulary, and our freedom, keep growing.
What is the 12-bar blues form?
It’s twelve bars of three dominant 7 chords in a set order. Adam lays it out in the video in F:
- Bars 1 to 4. F7, the I chord. Bar 2 often jumps to B flat 7 and back, which older blues players call the quick IV.
- Bars 5 and 6. B flat 7, the IV chord.
- Bars 7 and 8. F7 again.
- Bars 9 and 10. C7, the V chord, then B flat 7.
- Bars 11 and 12. F7, with a C7 at the very end to turn it around. Adam calls it that spicy V chord, played as a C7 sharp 9.
Every level below keeps that basic form and adds colors: different voicings, harmonic structures and devices.
Level 2: how do you turn a 12-bar blues into a jazz blues?
Add ii-V progressions. Instead of going from the V to the IV in bars 9 and 10, play a ii-V there, G minor 7 to C7, and think of it as a tension point. It gives you a lot of room for creating more tension on the way back home.
In jazz we also add ii-Vs that lead to the anchor points of the song. Bar 5, where we hit the IV chord, is one of them, so a little ii-V leads into it. Here’s the version we play in the video:
- Into bar 5. C minor 7 to F7 with a flat 9, a ii-V that lands on B flat 7.
- After the IV. A sharp IV diminished chord, B diminished 7, just for a little color.
- Just before bar 9. D7 instead of more F. D7 is the V of the ii, so it leads to G minor.
- Bars 9 and 10. G minor 7 to C7.
- The turnaround. D7, G minor 7, C7.
Replacing that V to IV with a ii-V immediately puts the blues in jazz territory, and all the jazz and bebop vocabulary for ii-Vs comes along with it. For those changes broken down further, the blues guitar chords lesson builds a jazz blues in F from small chord devices.
When we solo on these changes, we’re really expressing the chords: paying attention to what’s happening harmonically and articulating the chords in a melodic way that highlights each change. Everything we learned before is still possible. You can totally jam on one note, or on F pentatonic, or on different pentatonics. You can choose any colors, and also pay attention to that ii-V and express that motion. It’s optional. It’s kind of like someone is offering an apple: you don’t have to eat it, but it’s probably kind of cool.
Level 3: what’s a tritone substitution in a blues?
It’s swapping a dominant 7 chord for the dominant 7 chord a tritone away. Adam explains it in the video: the tritone sub of F7 is B7, and it works because the 3rd and the 7th of F7 are shared with B7. The functions are just flipped.
F7’s 3rd is A and its 7th is E flat. In B7, that same A is the 7th, and E flat (spelled D sharp) is the 3rd. Those two notes carry the sound of a dominant chord, so the swap adds color and still works.
In a blues you can do it with any of the dominant 7 chords. One nice spot is the ii-V into bar 5. Normally C minor 7 goes to F7. Use B7 instead, and it moves very nicely, a half step down, to the target, B flat 7. If you’re feeling adventurous, Adam’s next step is to add the ii of the tritone sub too: F sharp minor 7 to B7. That really pulls your ear outside the key, which is fun.
Level 4: what’s a bebop blues like Blues for Alice?
Charlie Parker’s Blues for Alice takes the format of a blues and puts even more bebop vocabulary on it. It’s a lot of ii-V motion through the cycle of fifths. Here’s how it usually goes in F:
- Bar 1. F major 7. That’s unusual for a blues, where we always think of the dominant F7.
- Bar 2. E minor 7 flat 5 to A7, a minor ii-V to the 6th degree.
- Bars 3 and 4. D minor 7 to G7, then C minor 7 to F7, ii-V after ii-V down to the IV.
- Bars 5 and 6. B flat 7, then B flat minor 7 to E flat 7. The IV goes to the minor IV, and this is where the cool stuff really happens.
- Bars 7 and 8. A minor 7 to D7, then A flat minor 7 to D flat 7, a ii-V on the flat III.
- Bars 9 to 12. G minor 7, C7, and a turnaround. We’re back in regular territory.
How do we go from playing the blues, a 12-bar blues, good old-fashioned blues, and try to be more free, more creative?
Rotem Sivan
A lot of times in jazz we learn a lot of options, and those options give us freedom of expression. If you can only make one salad, it might be a good salad, but you’d get tired of eating it every day. The ii-V is the move that keeps showing up here, and the ii-V-I guitar lesson has ten levels of lines for it.
Level 5: how do you play freely over a 12-bar blues?
Use target points. Direct your attention to a certain point in the form and create a different path to it instead of the ordinary one we know.
In this level we can do whatever we want. It’s free, it’s jazz. But we’re still thinking about that very basic form of the blues: 12 bars, a IV chord in one place, a V chord in one place. We’re just taking different vocabularies and getting there in different ways, maybe a Giant Steps impression, maybe quartal harmony. The idea is to explore, to find colors and mess around with them.
A 12-bar blues practice idea for today
Take the Level 2 changes in F and play them slowly, in time, until the form is in your ears. Then solo over them twice. The first time, use only F pentatonic. The second time, keep the pentatonic for most of the form, but in bars 9 and 10 try to highlight G minor 7 and C7 with notes from those chords. If you want a few blues phrases to start from, the free 5 Licks Cheat Sheet is a PDF of five licks that work over any blues or rock track.
For a full framework, Simple Blues Soloing is about hearing, feeling and creating over the blues, so solos come from your ears instead of muscle memory. And if the 7th chords in these changes feel shaky, Jazz Chord Essentials rebuilds your chords from the ground up, from how a 7th chord is built to every inversion on the 4th, 5th and 6th string sets.
Frequently asked questions
What chords are in a 12-bar blues in F?
F7, B flat 7 and C7, the I, IV and V of F, all played as dominant 7 chords. A common version goes F7 for four bars (with B flat 7 in bar 2), B flat 7 for two, F7 for two, then C7, B flat 7, F7, and a C7 at the end.
What’s the quick IV in a blues?
It’s going to the IV chord in bar 2 and back to the I in bar 3. In F, the first four bars become F7, B flat 7, F7, F7. Older blues players call it the quick IV.
What’s a tritone substitution?
It’s swapping a dominant 7 chord for the dominant 7 a tritone away, like B7 for F7. It works because both chords share the same 3rd and 7th, A and E flat, with their functions flipped. In a blues, C minor 7 to B7 to B flat 7 is a smooth example.
What’s the difference between a blues and a jazz blues?
A jazz blues keeps the 12-bar form but adds ii-Vs, like G minor 7 to C7 in bars 9 and 10 instead of C7 to B flat 7, plus chords like D7 and a sharp IV diminished. Bebop blues tunes like Charlie Parker’s Blues for Alice go even further.
Get the basic form in F into your ears first, then add one level at a time and hear what each new color does.
