The Key of G, from the Armonía

G major harmonises to G – Am – Bm – C – D – Em – F#°; G minor to Gm – A° – Bb – Cm – Dm – Eb – F. A son in this key mostly alternates the tonic and the dominant; a ranchera adds the subdominant; a bolero reaches for the submediant and the supertonic on its way home.

Inside the armonía this instrument is the top of the armonía — five re-entrant strings whose open third is the highest open pitch on the instrument, so every strum lands as one tight treble block instead of a spread stack, and the shape below is not a voicing choice so much as a section instruction — the whole armonía strikes the same mánico in unison, on the same slot, or the chord stops being one event.

Learn the tonic, subdominant and dominant in G until the hand goes there unasked, and the repertoire in this key is largely playable before anybody names a form.