One of the big reasons people want to learn acoustic guitar is to sound like their heroes, and there have been fewer inspirations players that the original blues players of the Mississippi Delta. The blues is a peculiar style of music to study as it takes many of the rules learned in western harmony and theory and throws them out of the window, but it is still the subjects of countless guitar instructions. You will find it very difficult to listen to any guitar player and not detect a small hint of the blues in their playing; it has been such an inspirational style that I think it is very important to integrate it into your routine as you learn acoustic guitar.
The foundation of the blues is the chord progression underneath, and that will be the focus of this article. The aptly named ’12 bar blues progression’ is instantly recognizable to any aspiring guitar player, and from a beginners perspective its perfect as it only contains three chords.
This is where we see how many rules the progression breaks. The three chords contained in the progression are all ‘dominant 7th chords’, when played in from A, the first chord is A7. A7 is the 5th chord of in the key of Dmaj (D,E,F#,G,A,B,C#,D), and for those of you that have an understanding of modes, we are using the 5th mode, which is A mixolydian (A,B,C#,D,E,F#,G,A). This is all ok until you look at the second chord which is D7, the notes in this are D,F#,A,C. You can see that the note C is not in the key of A mixolydian/Dmajor, in actual fact this chord comes from a totally different key. The third and final chord throws another spanner in the works as it is constructed from yet another key; E7 contains the notes E,G#,B,D again you can see there is a note (G#) that is not in the key we started in.

As complex as this all sounds it really doesn’t matter as most of the musicians you hear play over this progression will not even be aware of the theory behind it. In fact, most of the people that solo over this will just use a minor pentatonic starting from the tonic of the first chord in the progression, in this case that’s A minor pentatonic (A,C,D,E,G) so from the get go they use a scale that doesn’t even fit over the chord they are playing over as the C clashed with the C# in the chords. But as I stated, this is a tried and tested progression that has had an irreversible effect on the music you know and love. Take your time with this progression and get to know it well, it will take you one step closer to you goal as you learn acoustic guitar.