The Key of B, Blues Guitar

B major harmonises to B – C#m – D#m – E – F# – G#m – A#°; B natural minor to Bm – C#° – D – Em – F#m – G – A.

A blues takes those tables as a starting point rather than a rule: it plays the tonic, the subdominant and the dominant all as dominant seventh chords, which no major key contains on its own — the first place the idiom and the textbook part company.

The guitar carries the rhythm under each sung line and the answering phrase in the gap the singer leaves after it. The grip below is what the rhythm hand keeps hold of through the bar, and the answering phrase usually starts from the same hand position, so the shape doubles as a map of where the next lick begins.