Watch the Marco Cohen Rides Again online guitar lesson by David Hamburger from Essentials: Fingerstyle Blues
I was first exposed to dropped-D tuning while learning arrangements from Stefan Grossman’s Guitar Player column in the late 1970s. Two things were immediately apparent: one, dropped-D tuning makes all of your D chords sound amazing, and two, you have to learn new fingerings for most of the rest of the chords you thought you already knew. But only most. In Marco Cohen Rides Again, the root of the IV chord, G, is played at the 5th fret of the low E string, but the Aminor and C chords are unaffected because their roots are on the 5th string.