Basics Of Blues Guitar Chords: Playing The Twelve Bar Blues

In Five Essential Blues Keys

In this article, you'll learn how to play the twelve bar blues. The twelve-bar blues is the foundation for many blues songs. 

Blues Guitar Chords You'll Need For This Lesson

If you don't know how to play the guitar chords listed above, see my article Blues Guitar Chords Tutorial: 7 Essential Blues Guitar Chords.

How to read the chord diagrams

The Guitar articles on this site use standard graphical chord diagrams. You may already know how to read chord diagrams like this, but just in case you don't, here's a quick course in how to read them: How To Read Guitar Chord Diagrams

Basic Structure of the Twelve Bar Blues
The twelve bar blees progression is the foundation of blues guitar playing. There are other blues guitar progressions, but the majority of blues songs are based on the twelve bar blues. It's called "twelve bar blues" because the chord progression contains twelve measures, or bars. Each bar contains four beats. A twelve bar blues, then, has twelve four-beat measures.

One-Four-Five
The twelve bar blues is a "One-Four-Five" progression. No matter what key you play it in, the twelve bar blues uses three chords from that key: the One chord, the Four chord, and the Five chord. These chords are also sometimes identified with numbers or roman numerals. For example, the One chord may also be designated the 1 chord or the I chord. I'll use the roman numerals from now on.

So, what are the I, IV, and V chords? In any key, the I chord is the major chord with the same name as the key. It's called the I because the root note in the chord is the first note in the major scale in that key. So in the key of C, the C chord is the I. To find the IV and V chords, just count up the scale, starting at I. In C, where C is the I chord, I=C, II=D, III=E, IV=F, V=G. Therfore, in C, C is the I chord, F is the IV, and G is the V.

Back to the Twelve Bar Blues
Now that you know the meaning of the I, IV, and V chords, you're ready to learn the structure of the twelve bar blues progression. There are three sections of four bars each. The first section is four bars of the I chord. In C, this would be written as follows:

C / / / C / / / C / / / C / / /

In this notation, each chord name (i.e., C) or slash mark (i.e., /) is a beat. You play the named chord once for every beat. The slash marks just indicate that you stay on the same chord. The chord name (i.e., C) appears again at the start of each measure.

The second section of the progression has two bars of the IV chord followed by two bars of the I chord. Again, in C:

F / / / F / / / C / / / C / / /

The final section has a bar of the V chord, a bar of the IV chord, a bar of the I chord, and a final bar of the V chord. Again, in C:

G / / / F / / / C / / / G / / /

So to put it all together, one version of the twelve bar blues in C looks like this:

C / / / C / / / C / / / C / / /
F / / / F / / / C / / / C / / /
G / / / F / / / C / / / G / / /

The Seventh Chord Gives it "That Sound"
To get an authentic blues sound, you can add the 7th chord in some places. A seventh, or 7 chord is a chord that contains the note that is seventh in the scale. This is different from the I, IV, V numbering system; the Seventh in this case is part of the chord's letter name (like C7, D7, or G7). In the blues, you almost always will want to substitute a seventh chord for the V, and sometimes for the I. This just means, for example, that in C, where the V chord is G, you play G7 instead of G major. To keep it simple, just use 7th chords throughout the 12 bar progression:

C7 / / / C7 / / / C7 / / / C7 / / /
F7 / / / F7 / / / C7 / / / C7 / / /
G7 / / / F7 / / / C7 / / / G7 / / /

For a more authentic sounding blues, substitute the 7th chord for the V, and for the I and IV in certain places as well. We'll also go to the IV chord in the second measure to add variety (some players call this a 'quick IV' progression).

C / / / F / / / C / / / C7 / / /
F / / / F7 / / / C / / / C7 / / /
G7 / / / F / / / C / / / G7 / / /

Now that you can play the twelve bar blues in C, you can use your knowledge of essential blues guitar chords and the I, IV, V progression to play the blues in several keys. For more information, see my article Blues Guitar Chords Tutorial: 7 Essential Blues Guitar Chords.