Blues is a music genre that pioneered the rock music that we know today. Learning the guitar won’t be complete without learning about the blues and the ’12 bar blues’.
A 12 bar blues are basically a series of chord changes that repeats every 12 bars. A typical 12 bar blues will consist of only three chords also known as chord I, chord IV and chord V. The 12 bar blues format can be heard in recordings of many blues and rock legends such as Jimi Hendrix, Eric Clapton, BB King, Elvis Presley and many others.
Below is an example of the chord sequence in a 12 bar blues:
The example above is in the key of ‘G’, so G as the (I) ,C as the (IV) and D as the (V) chord. The D chord on the last bar are known as the ‘turnaround’, simply because it gives you the feeling of wanting to start over again from the (I) chord. When you’re ready to stop, just replace the D chord on the last bar with a ‘G’.
A common variation of the 12 bar blues is to perform a ‘quick change’ to the (IV) chord on the second bar before returning to the original format.
Here’s an example in the key of ‘E’.
In terms of the method to play it, the most favoured way to play the 12 bar blues is by playing a ‘riff’. Riff’s are short melodic ideas that are played in place of chords. A standard blues riff are played only on a few strings at a time and can be repeated over different chords in the progression. Playing riff’s makes the 12 bar blues sounds more interesting and are actually much easier to play compare to playing a full chord.
Check out ‘Before You Accuse Me’ performed by Eric Clapton that uses the ‘quick change’ variation of the 12 bar blues.
You should also check out ‘Red House’ by Jimi Hendrix that uses the same format.