Banjo G chord (Double C)G major on the 5-string banjo: 2 4 2 5, and 4 more shapes

Frets, string 4 to string 1: 2 4 2 5 (from the 2nd fret)

1. String 4 (C): 2nd fret, index finger (barre), D
2. String 3 (G): 4th fret, ring finger, B
3. String 2 (C): 2nd fret, index finger (barre), D
4. String 1 (D): 5th fret, little finger, G
5. String 5, the short g: open, G, in the chord

Sounds: D B D G  ·  G is G, B, D (1 · 3 · 5)

Found in: G major (I), D major (IV), C major (V), G mixolydian (I), A mixolydian (♭VII), D mixolydian (IV)

The 5th string: the short g is the root of G, so let it ring.

Double C tuning: gCGCD, the short 5th string first, then strings 4 to 1.