The 12-Bar Blues
In C it is C7, F7 and G7, laid out over twelve bars in a fixed order. All three are dominant sevenths, including the one you call home, and that is what makes the form sound the way it does.
- 12 bars
- 3 chords
- 10 songs below
same family
The progression
I7 - IV7 - V7, across twelve bars
Why it works
The strangeness is that all three chords are dominant sevenths, including the one on home. In ordinary tonal music that is impossible: a dominant seventh on the tonic should want to resolve away from itself. In blues it does not, because the flattened seventh comes from the melody rather than from harmonic function. The form works by repetition and by where the changes land, not by tension resolving.
Hear it in context
Ten songs on the same twelve bars, from a 1936 delta recording to a 1995 hit. The form outlived every style that borrowed it.
- Sweet Home Chicago
- Kansas City
- Rock Around the Clock
- Hound Dog
- Tutti Frutti
- Johnny B. Goode
- Crossroads
- Before You Accuse Me
- Pride and Joy
- Give Me One Reason
Make it yours
- Add the quick change
Going to the IV in bar two is the most common variation and it stops the first four bars sitting still.
- Put a turnaround in
The last two bars can push back to the top instead of resting, which keeps a long performance moving.
- Try it in minor
Minor blues changes the chords and keeps the form, and it sounds like a different genre.
When to reach for it
Any blues, most early rock and roll, and a great deal of jazz. Also as a practice frame: a known form to improvise over is worth more than any exercise.
When to leave it alone
When you want harmonic surprise. Everyone in the room knows where bar nine is going, which is a strength in a jam and a weakness on a record.