Banjo B chord (Double C)B major on the 5-string banjo: 3 4 3 4, and 2 more shapes

Frets, string 4 to string 1: 3 4 3 4 (first position)

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

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

Found in: B major (I), B mixolydian (I), E major (V), F♯ major (IV), F♯ mixolydian (IV), D♭ mixolydian (♭VII)

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.