Open C Tuning: A Player's Guide
Open C is the deepest open tuning there is: a low C drone, three roots, and only one 3rd, right at the top. It's a tuning for big ringing fingerstyle, drones and slide.
The guide covers getting there without wrecking your low string, the neck as a chord lookup table, working the bar, and the blues moves. There are 18 playable shapes, 12 full-neck chord maps and 8 scale maps in intervals, plus three phrases in tab, including a melody over the drone.
It's also straight about the tuning's quirks. With only one 3rd, most slide positions sound like power chords unless you include the top string. Some players love that and some don't. Either way, you should know before you retune.
16-page printable PDF, US Letter.