12 Bar Blues Form

          The 12 bar blues form is a simple harmonic progression that is played across 12 measures (or bars) of music. This harmonic progression consists mainly of the I, IV and V chords. The chords can exist as either simple triads or seventh chords, but the seventh chord version does not follow the normal structure of diatonic seventh chords. In a normal diatonic chord progression there is only one dominant seventh chord (the V7 chord). However, blues music lends itself to dominant seventh harmony. Therefore, all three chords (I, IV and V) can be played as dominant seventh chords even though this introduces pitches that are chromatic to the key.

          In addition to this chromaticism, blues music also is known for having loose boundaries between major and the parallel minor. Chords are often played with a minor third that slides or bends into a major third. This technique adds to the blues flavor of the sonic texture.

          The 12 bar blues form is used primarily in the blues style of music, but is also found in many pop, rock and gospel songs. These styles can tend to be heavily influenced by the blues style. The form is popular among musicians, because the simple repeating harmonic pattern causes it to be easy to memorize. Musicians can play most 12 bar blues songs without a lead sheet. All they need to know is the key of the song.

          The basic pattern for the 12 bar blues can be broken into three groups of 4 measures each. The first four measures consist of the I chord. Then there are two measures of IV and two measures of I. Finally there are two measures of V and two measures of I.




          There are many variations on the basic 12 bar blues pattern. The most common variation is the “Quick to IV.” The basic blues is known for the fact that each chord lasts for at least two measures. In this variation, a IV chord is substituted into the 2nd and 10th measures. This causes two instances where the IV chord is played for only one measure. In addition, the V chord (in the 9th measure) only lasts for one measure.

          In any version of the 12 bar blues (basic or variation) a V chord can be substituted for the final I chord. This substitution is used to lead back to the top when repeating the form. When ending the form, the musicians play a I chord for the final measure.

          Another variation is the minor 12 bar blues. In this variation every I and IV chord become a minor i and iv chord. In addition, the last group of four measures consists of a bVI for one measure, a V7 for one measure and then a i for two measures.



          There are many other variations on the 12 bar blues (Jazz Blues, Bebop Blues, etc.). I don’t have the time to list and discuss them all in this lesson. However, all of these variations are derived from the same basic 12 bar blues structure. They just add various transitional chords to different parts of the structure.

This Learning Music With Ray video discusses the 12 bar blues form.  In it, I discuss the structure and musical elements typical of this form.  I then play through the basic 12 bar blues (and some basic variations) with simple block chords in the key of C major.  Finally, I demonstrate several piano playing techniques that help to enhance your performance of a 12 bar blues beyond basic block chords.