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An Explanation of The Twelve Bar Blues

by

John Watts

(The sound is 36 bars long --give it a minute to load - - to hear it again, hit reload)

Standard Twelve Bar Chord Pattern is 4/4 time (4 beats per measure, 1/4 note = 1 beat)

(As played -- Key of G -- chords played as 1/4 notes (1 beat per chord), 4chords per measure or bar)

GGGG,  GGGG, GGGG, GGGG, CCCC, CCCC, GGGG, GGGG, DDDD, CCCC, GGGG, GGGG
   1        2        3        4       5        6        7       8        9      10      11      12

The 12 bar blues is based on what is known as the 1-4-5 chord progression (usually written in Roman numerals as I-IV-V) The 1, 4, and 5 chords are determined as follows: The #1 chord is the chord of the song key, so if the song is in G, then a G chord is the # 1 chord (a chord being several notes played together that harmonize with each other). The G chord consists simply of 3 notes G, B, and D. On your C harp the draw 2 is G, draw 3 is B, and draw 4 is D. Play them together and you have a G chord. The target note for the #1 chord is G, which can be found at 2 draw, 3 blow, 6 blow, and 9 blow, but if you play a G, a B, or a D while a G chord is playing it will "fit" and sound good, or at least not clash.

To determine the 4 and 5 chords you just count up from the #1 chord (remember, notes in music only go up to G then start over a A): G=1, A=2, B=3, C=4, D=5, E=6, F=7, G=1 (again) --- so for the key of G the 1, 4, and 5 chords are G, C, and D respectively. (also the target notes are G, C, and D for the appropriate chord)   If you are playing in another key, just determine the I-IV-V the same way, but start the #1 with the proper key.  

A    B    C    D    E    F    G    A    B    C    D   E    F    G
2    3    4     5    6    7    1    2    3    4    5   6    7    1

The 1-4-5 chord progression works like this - four measures of the 1 chord, two measures of the 4 chord, two measures of the 1 chord, one measure of the 5 chord, one measure of the 4 chord, two measures of the 1 chord. Add up all of the measures and you get 12 measures (or "bars"). For a song, just repeat the pattern over and over. The main variation on this is that often the last measure in a 12 bar pattern will be played as a 5 instead of a 1, especially if the song is continuing, and then at the end of the song the 1 is used on the 12th bar. Each measure consists of 4 beats (just count out 1, 2, 3, 4). So to write out a standard 12 bar progression, the chords for each measure would be as follows: G, G, G, G, C, C, G, G, D, C, G, G (or D if the song continues) With this in mind, go back and listen to the 12 bar progression on this page by hitting reload and see if you can follow that pattern in the playing.

G

G

G

G

C

C

G

G

D

C

G

G or D

When you improvise, try to hit the right target note during the underlying chord in the progression, or a note in the chord being played - it will always fit.