Banjo F6 chord (Open G)F sixth on the 5-string banjo: 3 2 1 0, and 6 more shapes

Frets, string 4 to string 1: 3 2 1 0 (open position)

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

Sounds: F A C D  ·  F6 is F, A, C, D (1 · 3 · 5 · 6)

The 5th string: the short g adds the 9th over F6, a colour rather than a clash.

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