Here’s a sound—a color—that I really enjoy throwing into a blues in G: the intriguing chord known as G13b9 [Ex. 1]. You don’t have to play this chord with the root, but to get a complete sense of the harmony—especially if there’s no bass player holding down the tonic—you can fret the root by putting your thumb on the lowest string at the 3rd fret as shown. A simple example of how you can bring out this harmony in a G blues solo would be a lick like this [Ex. 2]. This phrase comes straight out of the G half/whole symmetrical scale [Ex. 3]. G13b9 is just a prize chord for this scale, because the scale tags every note in the chord perfectly.
I’d like to point out that while the technical name of this chord is G13b9, I really don’t think of it that way. To me, it’s an E triad superimposed over G7. See the perfect E triad in the chord? It resides on the highest three strings. One way you can use this triad is in a lick like this [Ex. 4]. This phrase leads you smoothly into C7, the IV chord [which occurs in bar 5 of a typical 12-bar cycle].
And remember: Anything you create with the symmetrical scale can be shifted up the neck in minor thirds, and it’ll still remain diatonic to the scale. For instance, play a G triad followed by the E triad we’ve been working with, and then repeat those two shapes up a minor third [three frets], then up another minor, and so on. You end up with this cool progression [Ex. 5]. This up-in-minor-thirds tactic will lead you to wild licks like this [Ex. 5]. This ascending riff takes place over G7 and, by ending on Bb [the b7 of C7], we again land squarely on the IV chord. —As told to Jude Gold.