C# is a major, spelled C#, E# and G#. In Open G tuning (D2 G2 D3 G3 B3 D4) the easiest shape is x66666, which sits at fret 6, needs a barre across 5 strings at fret 6 and mutes 1 string. 12 positions for it are shown below, from the nut up to fret 13.
Notes and intervals
Note
C#
E#
G#
Interval
1P
3M
5P
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.
x66666sits at fret 6, needs a barre across 5 strings at fret 6 and mutes 1 stringx13123sits at fret 1, needs a barre across 3 strings at fret 1 and mutes 1 stringxx1110911sits at fret 9, spans 2 frets and mutes 2 stringsx63663sits at fret 3, needs a barre across 4 strings at fret 3 and mutes 1 string11101110xxsits at fret 10, needs a barre across 3 strings at fret 10 and mutes 2 stringsx6362xsits at fret 2, spans 4 frets and mutes 2 stringsx1315131415sits at fret 13, needs a barre across 3 strings at fret 13 and mutes 1 stringxx11131415sits at fret 11, spans 4 frets and mutes 2 stringsx6666xsits at fret 6, needs a barre across 4 strings at fret 6 and mutes 2 strings666666sits at fret 6 and needs a barre across 6 strings at fret 6xxx666sits at fret 6, needs a barre across 3 strings at fret 6 and mutes 3 strings66666xsits at fret 6, needs a barre across 5 strings at fret 6 and mutes 1 string
Keys C# belongs to
C# is diatonic to 24 of the 96 keys this app knows, playing a different role in each.