But you’ll rarely see blues musicians or songwriters using I, IV, and V in their standard chord voicings. In the key of A major, the I – IV – V progression would be A major – D major – E major. The V, or the dominant chord, is where the tension is at its highest, making the resolution to the tonic chord that much sweeter. The IV functions as subdominant, making listeners feel the tension of moving away from their home base. The I or the tonic chord tells us the home key. They are by far the most important chords in this genre, with 8-, 12-, 16- and 24-bar long progressions built around them.
Think of the I, IV, and V chords as the fodder that fuels most blues chord progressions.
