The progression uses an approach that places it's focus upon open strings played around phrases in order to influence the sound of the harmony. The harmonic movement is of a, I-IV-V progression is the basis for this riff.
The riff begins with a slide from the 4th string, "A to B," on 7th to 9th frets. Under this slide lick we have a sustaining open 3rd string which acts to create the harmony of. "G Major."
At the end of this measure, a 16th-note triplet scale lick is used to bring in our second measure. Here, the "G Major" chord is further highlighted with open 3rd and 2nd strings. Another 16th-note lick is applied to complete the idea.
In our third measure the progression brings in the, "C and D," chords of this key. The color of each chord is produced between the bass-note (Root) and their interaction with the open 4th and 3rd strings. The "C" chord takes on a, "sus2" effect. And, the "D" chord has a "sus4" sound.
At the end of this progression we run across the sound of the Tonic Chord, "G Major," which applies open 4th, 3rd and 2nd strings.
Take your time developing the chord layouts and open string set-ups. The fingering isn't too difficult, but mixing the different licks along-side the open-string patterns and passing licks may cause some technical challenges. Enjoy!
Micro Lesson 233: "G Major" Open Chord Riff