The Key of A — Fiddle

A major harmonises to A – Bm – C#m – D – E – F#m – G#°; A minor to Am – B° – C – Dm – Em – F – G. Most of the country repertoire in this key lives on three of those chords — the tonic, the subdominant and the dominant — plus the relative minor when a song wants one darker turn.

The fiddle chair carries pads under the verse and the turnaround answer between vocal lines. A chord on a bowed instrument is really a choice of double stops — two strings at a time, drawn from these tones — plus the arpeggio the bow can walk through the rest of them.

Learn the tonic-subdominant-dominant grammar in A until your hand goes there without asking, then add the relative minor, and most of the repertoire in this key is already playable.