The Key of C — Guitar

C major harmonises to C – Dm – Em – F – G – Am – B°; C minor to Cm – D° – D# – Fm – Gm – G# – A#. 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 guitar chair carries the boom-chick floor — a bass note on the strong beats, a strum answering it on the weak ones: the shape below is what a right hand strums, and which bass note opens it decides how the boom half of boom-chick actually walks.

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