When you dig into blues compositions by B.B. King, Ray Charles, Chuck Berry, Jimmy Page of Led Zeppelin, Elmore James, and other blues guitarists, you may notice that harmonically speaking, these songs are more or less the same. The traditional 12-bar blues progression involves a fixed 3-chord progression, a fixed 5-6 note scale, and similar rhythmic patterns. These simple elements serve as the foundation of countless iconic blues guitar songs.