Banjo Am chord (Double C)A minor on the 5-string banjo: 0 2 0 2, and 6 more shapes

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

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

Sounds: C A C E  ·  Am is A, C, E (1 · ♭3 · 5)

Found in: G major (ii), C major (vi), G mixolydian (ii), D mixolydian (v), C mixolydian (vi), G dorian (ii)

The 5th string: the short g adds the ♭7 over Am, a colour rather than a clash.

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