Banjo B♭maj7 chord (Open G)B♭ major seventh on the 5-string banjo: 8 7 6 7, and 2 more shapes

Frets, string 4 to string 1: 8 7 6 7 (from the 6th fret)

1. String 4 (D): 8th fret, little finger, B♭
2. String 3 (G): 7th fret, middle finger, D
3. String 2 (B): 6th fret, index finger, F
4. String 1 (D): 7th fret, ring finger, A
5. String 5, the short g: open, G, not in the chord

Sounds: B♭ D F A  ·  B♭maj7 is B♭, D, F, A (1 · 3 · 5 · 7)

The 5th string: the short g adds the 6th over B♭maj7, a colour rather than a clash.

With a capo: on the 3rd fret it’s 0 0 0 4 (frets counted from the capo), an open Gmaj7 shape. Spike the 5th string at the 8th fret to keep it in tune with the capo.

Open G tuning: gDGBD, the short 5th string first, then strings 4 to 1.