|6||x or G||3rd fretfr.||optionalopt.|
Guitar chords in the key of C major:
Chord C13 notes: (G), C, E, Bb, D and A.
The note G on the sixth string is not required, but can be played on the 3rd fret if needed.
C13 - C dominant 13th guitar chord.
1(C), 3(E), 5(G), b7(A#/Bb), 9(D), 13(A).