Gdim is a diminished, spelled G, Bb and Db. In Open G tuning (D2 G2 D3 G3 B3 D4) the easiest shape is x08688, which sits at fret 6, spans 2 frets, lets 1 string ring open and mutes 1 string. 12 positions for it are shown below, from the nut up to fret 11.
Notes and intervals
Note
G
Bb
Db
Interval
1P
3m
5d
12 ways to play it
Ordered by how hard they are to fret, easiest first, one per position on the neck. Fret numbers are relative to the position marked beside each grid.
x08688sits at fret 6, spans 2 frets, lets 1 string ring open and mutes 1 stringx05325sits at fret 2, spans 3 frets, lets 1 string ring open and mutes 1 string5053xxsits at fret 3, spans 2 frets, lets 1 string ring open and mutes 2 stringsx01101111sits at fret 11, needs no stretch at all, lets 2 strings ring open and mutes 1 stringx08088sits at fret 8, needs no stretch at all, lets 2 strings ring open and mutes 1 string565088sits at fret 5, needs a barre across 3 strings at fret 5 and lets 1 string ring open50532xsits at fret 2, spans 3 frets, lets 1 string ring open and mutes 1 string53502xsits at fret 2, spans 3 frets, lets 1 string ring open and mutes 1 stringx0868xsits at fret 6, spans 2 frets, lets 1 string ring open and mutes 2 strings5350xxsits at fret 3, spans 2 frets, lets 1 string ring open and mutes 2 stringsx0532xsits at fret 2, spans 3 frets, lets 1 string ring open and mutes 2 stringsxx5325sits at fret 2, spans 3 frets and mutes 2 strings
Keys Gdim belongs to
Gdim is diatonic to 8 of the 96 keys this app knows, playing a different role in each.