Open G tuning

Open G, from the 6th string to the 1st: D G D G B D. Frequencies are for A4 = 440 Hz.

Open G tuning is D G D G B D, from the 6th string to the 1st. The open strings spell a G major chord: the root G on the 5th and 3rd strings, the fifth D on the 6th, 4th and 1st, and the major third B on the 2nd. The lowest note is D, not G, so with all six strings the chord has its fifth in the bass.

Only three strings move from standard, each by a whole step: the 6th and 1st go from E to D and the 5th from A to G. The middle three, D, G and B, are untouched, which makes open G one of the quickest open tunings to reach. Old blues guitar books call it Spanish tuning, after a 19th-century parlor piece, Spanish Fandango, that was played in it.

The top four strings of open G are the same notes as the four long strings of a 5-string banjo in open G: D3, G3, B3 and D4. Banjo rolls and licks on those strings can be copied note for note onto the guitar's top four strings in this tuning.

Use the unchanged strings as references. The 6th string should sound one octave below the open 4th string, and the 1st string one octave above it; the 5th string should sound one octave below the open 3rd string. Octaves are easy to hear, and the tuner confirms each one.

When you use the microphone, tap a string's button before you retune it. The tuner then stays on that string instead of guessing, which helps while the string is still far from its note. When all three are done, return to Auto and check all six, since loosening the thicker strings changes the pull on the neck a little.

Going back to standard is the same three strings in reverse: the 6th and 1st up from D to E, the 5th up from G to A. Tuning up comes naturally here, so the strings settle well, but check all six once more at the end.

A finger or a bar across all six strings at the 5th fret gives C, at the 7th fret D and at the 12th fret G an octave up: the three chords of countless songs in G. A slide works the same way, which is why open G, along with open D, is a favorite tuning for slide blues.

Minor chords come from the 2nd string, which holds the third: fret it one fret behind the bar. With the bar at the 2nd fret and the 2nd string at the 1st fret you get A minor; with the bar at the 4th fret and the 2nd string at the 3rd fret, B minor.

Keith Richards of the Rolling Stones famously plays open G on five strings, with the 6th string taken off. The lowest note is then the G on the 5th string, every barre chord has its root in the bass, and riffs like Brown Sugar and Start Me Up come from moving a few fingers over that open chord. You can try it without removing anything: just leave the 6th string unplayed.

Open G and open D are both major-chord tunings, and many players pick between them by the key of the song: open G for songs in G, open D for songs in D. Open G sounds higher and brighter and changes three strings; open D puts the root on the 6th string and changes four.

Put a capo at the 2nd fret and open G becomes open A (E A E A C♯ E), the same shapes two frets higher. That is the usual way to play open A material without tightening strings above their standard pitch.