What are the primary cords for the 12 bar blues?

The primary chords for the 12-bar blues are the I, IV, and V chords. In the key of C, for example, these would be C (I), F (IV), and G (V). The typical progression follows a pattern of four bars of the I chord, two bars of the IV chord, two bars back to the I chord, one bar of the V chord, one bar of the IV chord, and finally two bars of the I chord. This structure provides a foundation for improvisation and expression in Blues Music.