One of the best vehicles for learning improvisation is the blues, in part because it really is so simple. In this lesson we’ll look at the basic “12 bar blues” form and it’s near unlimited variations. By the end of this lesson you’ll better understand how to play a basic blues chord progression, and how to analyze and substitute chords.
Whether a simple blues or complex variation of it, these chord progressions are an ideal backdrop to practice single note improvisation. I recommend memorizing a basic blues chord progression before experimenting with solos, as this will be the framework from which you build. If you don’t play a harmonic “rhythm section” instrument (that is, one capable of playing more than one note simultaneously) try substituting each chord with just the root, and when comfortable alternatively play an arpeggio for each measure.
Above is an example of the a simple 12 bar blues in the key of F. This is probably the most simple and common variation, so we’ll begin with it as a starting point.
Now, if in the key of F major, we can numerically label each chord by interval and roman numeral. By thinking of a chord progression as a series of roman numerals, you’ll find it easier to memorize tunes, substitute chords, and play the song in different keys.
Upper case numerals signify a major chord, while lower case represent a minor chord. In a typical basic blues progression, all chords are generally played as dominant 7ths, but you can substitute these for major triads to keep things simple.
If you find this a bit confusing, bear in mind that each note of the major scale (or any scale for that matter) has an associated chord. This is done by harmonizing the major scale as seen below in C, which I roughly covered in my guitar triad lesson.
With the scale degrees made numeric, I have labeled the chords below in red as roman numerals. As you can see, this progression utilized the 1st ,4th & 5th scale degrees. This is what you often hear people refer to in blues and rock as a “one-four-five” progression.
With the above analysis in mind, I’ve added a chart below outlining possible variations which make use of chord substitutions. The cells highlighted in red indicate a change from the previous example, to help demonstrate how each variation is built upon the previous. A chord substitution is a somewhat involved topic that I will cover in future lessons, but in a nutshell substitutions introduce harmonic variety with alternate chords that are closely related to the original.
As you can see there are many possibilities, and things can get quite complex. However, at the end of the day these variations and substitutions still functionally serve the same roll of tonic, sub-dominant, and dominant to create musical anticipation, tension and resolution in the same measures as before.
Blues progressions are not musically new or novel from a historical perspective. For instance, examples of “one-four-five” progressions are prevalent in Baroque music. However, what “the blues” offer in terms of innovation may be the use of dominant 7th chords for I and IV (which would ordinarily be major 7th chords), the dotted eighth swing rhythm, and of course the infamous and obligatory “guitar-face” grimace.
Enjoy and have fun!
