The Key of Db, from the Armonía

Db major harmonises to Db – Ebm – Fm – Gb – Ab – Bbm – C°; C# minor to C#m – D#° – E – F#m – G#m – A – B. 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 bottom of the armonía — the same mánico the vihuela is playing, an octave lower and with more sustain, which is what stops the section sounding thin under a full melody. Nothing here is a solo grip: the value of the shape is that it lines up with the vihuela's, so the pair arrive in unison as one attack with a low half and a high half.

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