Banjo A7 chord (Open D)A seventh on the 5-string banjo: 2 3 4 5, and 5 more shapes

Frets, string 4 to string 1: 2 3 4 5 (from the 2nd fret)

1. String 4 (D): 2nd fret, index finger, E
2. String 3 (F♯): 3rd fret, middle finger, A
3. String 2 (A): 4th fret, ring finger, C♯
4. String 1 (D): 5th fret, little finger, G
5. String 5, the short f♯: open, F♯, not in the chord

Sounds: E A C♯ G  ·  A7 is A, C♯, E, G (1 · 3 · 5 · ♭7)

The 5th string: the short f♯ rubs against the G in this shape, a semitone away: some players let it ring, some skip it.

With a capo: on the 2nd fret it’s 0 1 2 3 (frets counted from the capo), an open G7 shape. Spike the 5th string at the 7th fret to keep it in tune with the capo.

Open D tuning: f♯DF♯AD, the short 5th string first, then strings 4 to 1.