12 Bar Blues is a pattern of chords which repeats every 12 bars. This progression is invaluable to the rock guitarist because of its use in many songs. For example, songs performed by Elvis Presley, Chuck Berry and the Beatles, such as "Hound Dog", "Johnny B. Goode" and "Roll over Beethoven" are all based upon a 12 bar progression (see Appendix Two).
Rhythm Pattern
You will notice that in the first line there is no chord symbol written over the 2nd, 3rd and 4th bars. It is unnecessary to repeat a chord symbol until an actual chord change occurs (e.g., at the 5th bar). This rule applies to all chord progressions studied in this book.