12 Bar Blues

Thanks to Lady D:

The twelve bar blues is one of the most important song forms in popular music, jazz, rock and folk music. Once you understand the twelve bar blues and its variations, you will understand hundreds of other songs guaranteed. It is really fun to play the blues. I love the sound of slow soulful blues played on the piano.

The twelve bar blues, the most common blues form, consists of three lines of four bars each. Each line consists of a two bar statement followed by an implicit response. Each measure is four beats since a lot of blues tends to be in four.

All of the forms use just three chords, and roman numerals are used to figure them. The first bar always refers to the I chord. The second bar is either the I chord again, or it can be quick change blues, which would be the IV chord. Bars 3 and 4 comprise the I chord again. Bars 5 and 6 will be IV chord, and so it goes.

12 Bar Blues Chords:

The I, IV, and V chords form the backbone of the blues. In most blues-based contexts, you can make the major chords into dominant sevenths (I, 3, 5, 7b) or even ninths (1, 3, 5, b7, 9).

I /// I /// I /// I ///
C C C C
IV /// IV /// I /// I ///
F F C C
V /// V /// I /// I ///
G /// G /// C /// C ///

A turnaround found in the last bar strongly propels the listener (and other musicians) back to the top for another round of playing. In more complex blues progressions, the turnaround often grows to two bars in length, then filling the eleventh and twelfth bar. Here is what I mean:

I (C) IV (F) I (C) I (C7)
IV (F) IV (F) I (C) I (C)
V (G) IV (F) I (C) V (G) turnaround

In much of early blues, the meter was anything but strict. Beats and bars were added and omitted freely, according to the whim of the performer. In fact, it could be said that early blues performers felt the music as a flow of beats rather than regular meter and phrase lengths. Todays blues are rigid and predictable in comparison. Any blues lover owes it to her/himself to check out early blues recordings.