Open G Tuning

The low-bass open G: a G major chord on the open strings with a D in the bass. Every string moves from C6, and a straight bar plays a major chord at every position.

The low-bass open G

Open G here is D G D G B D from the low string up: a G major chord with its fifth, D, in the bass. It is not the G B D G B D row that is also called open G; the two sources this page cites print the low-bass row under the name.

A straight bar plays a major chord at every position, G open, C at fret 5 and D at fret 7, and a bar or a slant spells the same five chord types as open E: the major and minor triads, the power chord, the dominant seventh and the 6sus2.

The retune

Every string moves from C6. String 4 moves furthest, five semitones down from G to D, and the two low strings move up, string 5 from E to G and string 6 from C to D. Luna Guitars sets it beside open A, the same row a whole step higher.

What moves from C6

Open G against C6, string by string, string 1 (the highest) first. Each move is the nearest one that reaches the new note.
String C6 Open G Move
1 E D down 2 semitones
2 C B down 1 semitone
3 A G down 2 semitones
4 G D down 5 semitones
5 E G up 3 semitones
6 C D up 2 semitones

Six of the six strings move. Struck open, the strings ring as G Major.

What a bar spells

Every chord type a straight bar or a slant spells in Open G or in C6. A type is spelled on all twelve roots or on none, because the bar slides.
Chord type C6 Open G
Major yes yes
Minor yes yes
Power (5) yes yes
7 — yes
m7 yes —
maj7sus2 yes —
6sus2 yes yes
6 yes —
m(add9) yes —

Open G spells five chord types to C6's eight: one gained, four given up.

Where this row comes from