Watch the Dominant 9th Chord online guitar lesson by TrueFire from Blues Guitar Greatest Hits Vol. 1
Lesson Source: Robben Ford's Blues Revolution
Chicago blues players not only electrified the blues, they added more sophisticated chords to the blues such as the 9th chord, which is used in place of the standard 7th. Robben demonstrates various applications of the 9th chords, both as full chords and as a very versatile triple-stop on the top three strings and continues his demonstration of what was then "new harmonic terrain for the blues" with an introduction to the 13th chord.