Banjo Bmaj7 chord (Double C)B major seventh on the 5-string banjo: 6 8 10 9, and 2 more shapes

Frets, string 4 to string 1: 6 8 10 9 (from the 6th fret)

1. String 4 (C): 6th fret, index finger, F♯
2. String 3 (G): 8th fret, middle finger, D♯
3. String 2 (C): 10th fret, little finger, A♯
4. String 1 (D): 9th fret, ring finger, B
5. String 5, the short g: open, G, not in the chord

Sounds: F♯ D♯ A♯ B  ·  Bmaj7 is B, D♯, F♯, A♯ (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.