12-Bar Blues: The Basics
As its name suggests, the 12-bar blues is a chord progression that spans twelve bars. It consists of a signature structure, but also features several common variations. In this lesson we’ll cover the basics of the 12-bar blues, how it’s structured, and some variations to get you strumming the blues.
I – IV – V Chords
The standard 12-bar blues progression is based around the I, IV, and V chords. Let’s take a look at what this means.
If we’re working in the key of A, we take the chords built on the 1st, 4th, and 5th degrees of the scale.
| Degree | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Chord | A | Bm | C#m | D | E | Fm | G#dim |
This gives us the chords A major, D major, and E major. However, in blues these chords are often played as dominant 7th chords, which would give us A7, D7, and E7.
With these chords in hand, let’s dive into the structure of the 12-bar blues progression.
12-Bar Blues Structure
While the 12-bar blues has several variations, the standard progression looks like this:
| I | I | I | I |
| IV | IV | I | I |
| V | IV | I | V |
This progression follows the sequence:
- I Chord – 4 bars
- IV Chord – 2 bars
- I Chord – 2 bars
- V Chord – 1 bar
- IV Chord – 1 bar
- I Chord – 1 bar
- V Chord – 1 bar
Using our I, IV, and V chords in the key of A, we get the following progression:
| A7 | A7 | A7 | A7 |
| D7 | D7 | A7 | A7 |
| E7 | D7 | A7 | E7 |
12-Bar Blues Variations
One of the more common variations you’ll see in the 12-bar blues structure looks like this:
| I | IV | I | I |
| IV | IV | I | I |
| V | IV | I | V |
In this variation, you only play the I chord for one bar before switching to the IV for a one bar, then back to the I for two more bars. The remaining 8 bars are unchanged.
Turnaround Variation
Another variation you’ll see comes in the turnaround section of the progression, which is made up of bars 11 and 12. In this variation, instead of moving to the V chord in the last bar, you hang on the I chord until the progression starts over again.
| I | I | I | I |
| IV | IV | I | I |
| V | IV | I | I |
Minor Blues Progression
Minor blues is played with the same 12-bar structure. With minor blues, you’ll see minor chords and/or minor 7th chords used for the i, iv, and v chords. You may also see a dominant V chord used, particularly in the turn around. This is what I’ve used in the B minor blues backing track below.
Wrap up
The 12-bar blues progression is a staple of blues music. It’s a common progression that all guitar players should have some familiarity with. Once you have the basics down, it’s fun to start putting some leads over top. The 12-bar structure also allows you easily transpose the progression and your lead playing to other keys. In a future lesson I’ll cover some simple ideas for playing over a 12-bar blues progression.
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