Everything Guitar Project :
: open tuning
Open tuning in contrast to standard tuning of a guitar means, that you have a chord with all the strings open. In standard tuning you normally have to fret at least 2 strings to form a chord (ex. is e: 022000).
A good chord to compare is G chord. Using standard tuning this chord is 320001. If you use Open G Tuning instead it is 000000.
Other often used open tunings are: