Stop 4 of 6
The 12-bar blues
The most famous form in popular music: I, IV and V.
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Stop 4 of 6
The most famous form in popular music: I, IV and V.
If popular music had a road map, the would be the main highway. Delta and Chicago blues travel along it, so do 1950s rock and roll, much of 60s and 70s rock, boogie, jazz and funk. It's just three chords in a fixed order, but knowing that form by heart lets you play with musicians you've never met. At this stop you learn it in two keys and understand why it works.
Start the backing and listen without playing. Follow the box that lights up: there are twelve, and when the last one ends it starts again. Try to notice the moments when the music "leaves home" and when it "comes back".
You probably noticed three moments: the first four bars at home, a trip to another chord in bar 5, and a zone of greater tension in bar 9 that pushes back to the start. That feeling of a cycle is the form.
The form is organised in three four-bar phrases. Here's how it looks on a , the simplified score almost every blues musician uses:
| Bar 1 | Bar 2 | Bar 3 | Bar 4 | |
|---|---|---|---|---|
| Phrase 1 | A | A | A | A |
| Phrase 2 | D | D | A | A |
| Phrase 3 | E | D | A | E |
Each phrase has a role:
Why A, D and E? Write out the notes of the A major scale and number them:
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|
| A | B | C♯ | D | E | F♯ | G♯ |
The chord built on note 1 is called I; on note 4, IV; on note 5, V. They're written as to keep them apart from fret or finger numbers. These three are the key's .
| Key | I | IV | V |
|---|---|---|---|
| A | A | D | E |
| E | E | A | B |
| G | G | C | D |
| C | C | F | G |
A guitar shortcut: if you play the I with its root on the 6th string, the IV is at the same fret on the 5th string, and the V is two frets higher on the 5th. It's the same pattern at any fret.
String 6, Fret 5: A2 · 1 · Scale tone
Between them they contain every note of the scale: the I has A, C♯ and E; the IV, D, F♯ and A; the V, E, G♯ and B. Also, the IV and the V sit the same distance from the I, one below and one above (a fifth), so they "pull" on the I from both sides. The V creates the most tension and asks most strongly to return: that's why it closes the form. This is only a preview: in Harmony City you'll study these functions in detail.
Ear test: hear the bass move from I to IV and from I to V.
First, the three power chord shapes you'll use, all open:
Play eight eighth notes per bar, downstrokes, with a light palm mute. Here's the first bar:
If you prefer full chords, the form is the same with A, D and E strummed:
E is a favourite key for blues guitarists because the open 6th string is the root. The V is B5, which has no open version: use the movable shape on the 5th string, fret 2.
Bars 11 and 12 are called the : their job is to take you back to bar 1. The V in bar 12 creates the tension that the I in bar 1 resolves. Many guitarists decorate these two bars with a short phrase. Here's a simple original one: the bass climbs from A to the E5 in bar 12, and then waits.
At the end of the song, the last bar 12 doesn't go to the V: it ends on the I, so it sounds like a full stop.
A very common variant is the . Bar 2 visits the IV and bar 3 returns to the I. It adds movement to the first phrase, which is otherwise very static.
At a jam it's normal to ask before starting: "quick change or not?".
The 12-bar form is the most common, but not the only one. There are 8-bar blues, shorter and often with more chords, and 16-bar blues, which stretch one of the phrases. There's also the minor blues, with minor chords on the I and IV and a darker sound. Many early Delta blues didn't stick to a fixed number of bars at all: the guitarist stretched or shortened a phrase to follow the voice, since they played alone and didn't have to coordinate with a band. The 12-bar form became standard mostly once the blues began to be played by groups and published as sheet music and records.
Goal: Play three rounds of the form in A in a row, without looking at the chart and without losing your place.
Play the blues in E with a quick change (bar 2 on A5). In bar 12, play a single B5 on beat 1 and let it ring through the other three beats while you count.
Goal: Play two rounds in E with the quick change, entering bar 1 exactly on time after bar 12.
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