12 Bar Blues
Music Theory Resources
One very common chord progression in popular music is the 12-bar blues. The harmonic pattern is quite simple: I-IV-I-V-I. To fill 12 measures (or bars) of music with these chords, the first I is repeated for the first four bars, then each of the remaining chords is used for two bars each:
This pattern may seem predictable and repetitive, but these features make the 12-bar blues a good framework for improvised solos, which are an important part of both jazz and rock. The blues genre and this blues progression were major influences in the development of both jazz and early rock 'n' roll.
Here are some examples of songs that use the 12-bar blues: