Watch the Lesson 18 online guitar lesson by David Hamburger from Fingerstyle Blues Handbook 1

Once you get comfortable playing in E, A and dropped D tuning, you may want to venture out into the world of open tunings. The two most common tunings for solo blues guitar are open D (DADF#AD, low to high) and open G (DGDGBD, low to high). In each of these tunings, your guitar is tuned to a complete open chord, creating new possibilities for open strings in the bass and for new chord voicings on top. >> Reference Source: Open Tuning (