This week in the Song Factory, we begin talking about the conventions of the blues. One central convention is the twelve-bar form. It’s so closely associated with the blues generally that jazz musicians use the term “a blues” to mean any tune using the twelve-bar form. However, it is surprisingly difficult to define what the twelve-bar blues actually is. That’s because there is no such thing as “the” twelve bar blues. Instead, there is a vast constellation of blues song forms that share some general structural features in common. In this post, I won’t even begin to list every variant; I’ll just give some representative examples. For the real truth about this music, you need to consult the music itself.
Twelve bar blues famously uses the I, IV and V chords. If you are unfamiliar with Roman numeral notation, it’s easier than you would think. Pick any key, say, C. The I chord will be C. Simple! Now think of the C major scale. The IV chord will have its root on the fourth scale degree, F. The V chord will have its root on the fifth scale degree, G. If you are in the key of A, then the I chord is A, the IV chord is D, and the V chord is E. If you are in the key of E-flat, then the I chord is Eb, the IV chord is Ab, and the V chord is Bb.
You can use the circle of fifths to quickly find the I, IV and V chords in any key. Pick any slot on the circle as your I chord. The IV chord will be one slot counterclockwise, and the V chord will be one slot clockwise.
You can add chord extensions to your Roman numerals just like you can for regular chord symbols. So in C, the I7 chord is C7, the IV7 chord is F7, and the V7 chord is G7. In the blues, you usually play everything as seventh chords.
In the rest of this post, I walk you through some widely played versions of the twelve-bar blues. I represent each one using a circular diagram. Each wedge of the circle is a measure of 4/4 time. Read clockwise starting from the top. A blank measure means that you keep playing the chord from the previous measure.
Simplest
This is the minimalist version of twelve-bar blues. There’s a lot of space here for your own riffs and embellishments.
Examples
“When The Levee Breaks” by Memphis Minnie and Kansas Joe McCoy (B-flat)
| Bb7 | Bb7 | Bb7 | Bb7 | | Eb7 | Eb7 | Bb7 | Bb7 | | F7 | F7 | Bb7 | Bb7 |
“Walking Blues” by Robert Johnson (B)
| B7 | B7 | B7 | B7 | | E7 | E7 | B7 | B7 | | F#7 | F#7 | B7 | B7 |
“Billie’s Blues” by Billie Holiday (B-flat)
| Bb7 | Bb7 | Bb7 | Bb7 | | Eb7 | Eb7 | Bb7 | Bb7 | | F7 | F7 | Bb7 | Bb7 |
“As Long As I’m Moving” by Ruth Brown (D-flat)
| Db7 | Db7 | Db7 | Db7 | | Gb7 | Gb7 | Db7 | Db7 | | Ab7 | Ab7 | Db7 | Db7 |
I labeled this as the “simplest” twelve-bar blues, but that isn’t actually true. It’s the simplest version that uses the I, IV and V chords. However, sometimes blues artists will leave out the V7 chord from this form, and replace it with IV7 or I7. Lightnin’ Hopkins does this a lot. There is an even simpler version of the form that also leaves out the IV7 chord and just stays on I7 the entire time. This is called one-chord blues, and it’s a favorite form of Howlin’ Wolf and John Lee Hooker.
Simple
The only difference between this and the “simplest” twelve-bar blues is the IV7 chord in measure ten. This breaks up the V-I cadence and inserts a more bluesy-sounding IV-I that matches the one between measures six and seven.
Examples
“Long Tall Mama” by Big Bill Broonzy (C)
| C7 | C7 | C7 | C7 | | F7 | F7 | C7 | C7 | | G7 | F7 | C7 | C7 |
“I’m Ready” by Muddy Waters (E-flat)
(He adds four extra bars to the first line of the form on the second and third verses.)
| Eb7 | Eb7 | Eb7 | Eb7 | | Ab7 | Ab7 | Eb7 | Eb7 | | Bb7 | Ab7 | Eb7 | Eb7 |
“Why I Sing the Blues” by BB King (C)
| C7 | C7 | C7 | C7 | | F7 | F7 | C7 | C7 | | G7 | F7 | C7 | C7 |
Default
This is the version of the twelve-bar blues I most often see in music teaching materials. It’s surprisingly hard to find examples of it, though!
This form is the same as the “simple” version, but it adds a V7 chord in the last bar, creating a V-I cadence with the beginning of the next time through the form.
Examples
“Blues for Mama” by Nina Simone (B)
| B7 | B7 | B7 | B7 | | E7 | E7 | B7 | B7 | | F#7 | E7 | B7 | F#7 |
Quick to four
This variant on the “default” version inserts the IV7 chord in the second measure. It’s also common to play IV7 in the second measure of the simple and simplest versions of the twelve-bar blues.
Examples
“Sweet Home Chicago” by Robert Johnson (F)
| F7 | Bb7 | F7 | F7 | | Bb7 | Bb7 | F7 | F7 | | C7 | Bb7 | F7 | C7 |
“Standing Around Crying” by Muddy Waters (E)
| E7 | A7 | E7 | E7 | | A7 | A7 | E7 | E7 | | B7 | A7 | E7 | B7 |
“The Sky Is Crying” by Elmore James (D)
| D7 | G7 | D7 | D7 | | G7 | G7 | D7 | D7 | | A7 | G7 | D7 | A7 |
Jazz
Jazz musicians have extended the blues formula in uncountably many ways. It’s much too big a subject for this post. Here I’ll just talk about one possible version of twelve-bar blues as played by jazz musicians: take one of the standard folkloric forms and replace the V7-IV7 in measures nine and ten with ii-V instead.
Examples
“Fine and Mellow” by Billie Holiday (E)
| E7 | A7 | E7 | E7 | | A7 | A7 | E7 | E7 | | F#m7 | B7 | E7 | B7 |
“Now’s The Time” by Charlie Parker (F)
| F7 | Bb7 | F7 | F7 | | Bb7 | Bb7 | F7 | F7 | | Gm7 | C7 | F7 | C7 |
“Jeep’s Blues” by Duke Ellington (F)
| F7 | Bb7 | F7 | F7 | | Bb7 | Bb7 | F7 | F7 | | Gm7 | C7 | F7 | C7 |
Here’s a (hypothetical) more complicated jazz blues.
Going further
This list barely scratches the surface. It doesn’t include minor blues at all, because I’ll cover that in a different post. Canonical examples include “The Thrill is Gone” by BB King and “Equinox” by John Coltrane.
There are also some idiosyncratic twelve-bar blues progressions that occur only in one specific tune, but that are nevertheless famous. For example, check out the rising and falling minor seventh chords in “Stormy Monday” by T-Bone Walker.
The twelve-bar form is only one possible blues song structure. “Watermelon Man” by Herbie Hancock is a sixteen-bar blues. And there are plenty of blues songs that use forms from country, ragtime, or folk songs. That, again, is for another post.
Finally, there are many non-blues songs that use the twelve-bar form and changes, including the 1960s Batman theme song and “Shuckin’ the Corn” by Flatt and Scruggs. Or are these tunes secretly blues too?
This is great! Thanks for doing this write-up. I have people I’d love to share this with you. It’s also nice to have this playlist of variations on the same musical idea.
One thing that has helped me write, perform, and solo over 12-bar blues tunes (especially more complex, faster versions with changes I struggle to keep up with) is to think about them all as a basic, 6-part call and response structure: A – A | B – A | C – A. This has helped me with that change the amount of measures in part but otherwise keep the same structure (e.g. Wayne’s Shorter’s “Adam’s Apple”, a 24-bar form that follows this structure even though it uses bVII instead of IV; or “Aquatic Ambiance” from Donkey Kong Country, which is not at all a blues but is a 12-bar form made of 6-part structure and a melody that I hear as call-and-response).
I like your mental concept of the blues, it makes perfect sense.