Watch the G On Top online guitar lesson by Brad Carlton from Chord Studies: Evolving Blues Vol. 2
This group of four chords is in a C blues format. We start off with a C7 chord using the A7 form. Then we go up to the F9 which we fret not with our second, first and third finger, but in this case we use our second, third and fourth fingers. The reason we use this fingering is so that when we slide down to the E♭9 you can rotate your hand diagonally so that you can clear the first string with the fourth finger barre. Notice that throughout the progression we have a constant G note in the top register of the chords.