Banjo D7 chord (Double C)D seventh on the 5-string banjo: 2 2 0 4, and 6 more shapes

Frets, string 4 to string 1: 2 2 0 4 (open position)

1. String 4 (C): 2nd fret, index finger (barre), D
2. String 3 (G): 2nd fret, index finger (barre), A
3. String 2 (C): open, C
4. String 1 (D): 4th fret, ring finger, F♯
5. String 5, the short g: open, G, not in the chord

Sounds: D A C F♯  ·  D7 is D, F♯, A, C (1 · 3 · 5 · ♭7)

The 5th string: the short g rubs against the F♯ in this shape, a semitone away: some players let it ring, some skip it.

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