A standard 12-bar blues progression includes chords built on the first, fourth and fifth degrees of a major scale and all three chords are usually dominant seventh in quality (I7, IV7 and V7).
For example, a basic 12-bar blues chord progression in the key of A includes the I7, IV7 and V7 chords in that key — A7, D7 and E7, respectively (fig.1).
But it’s not uncommon to substitute more colorful chords for the basic seventh chords in a 12-bar blues chord progression.
This post will look at some chords commonly used as substitutes in a 12-bar blues and provide a few examples of how to work them into a progression.
It will also cover minor blues harmony, the chords used in a 12-bar blues chord progression played in a minor key.
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