This descending chiming riff is a real gem and it's simple to play,but be sure to have a bright, clear tone on the quitar. Here it is........
E-----15-----13-----12-----10-----15-----13-----12-----10-----8-----E
B-----12-----10------9------7-----12-----10------9------7-----5-----B
G-----12-----10------9------7-----12-----10------9------7-----5-----G
D-----12-----10------9------7-----12-----10------9------7-----5-----D
A-------------------------------------------------------------------A
E-------------------------------------------------------------------E
Strumming; Strum the whole chord once on the downstroke then just strum the top two/three strings double time. Keep the right hand loose and you will get that ringing sound.
The theory; There are several ways to look at this riff. I think of it this way. The chord shape is a major shape without the root bass note. Instead the chord tonic is put on the top, the E string.
This creates an octave on the E and G strings with the third in between. That's the payoff. Played on the high strings this creates the harmonious chiming.
Now if you haven't already clicked back to pictures....let me take it further.
The chord shape is moved intact , i.e. no fingering change. This is called parallel motion. If you do this to this extent you are either musically naive or musically sophisticated. I think we know where we stand here.
Normally this would sound stilted or modal. Here, I think the sense of descending motion and the ringing tone just obliterate the usual mechanical feeling of the parallel motion.