This. Yes. I'd see it as a more "traditional", or "folk/downhome", approach to the blues, as opposed to the more chord-based approach you find in jazz (which culminates in Blues For Alice ). Most of the time, of course - as I think you'd agree - we work with the interplay between both approaches. OK, so why are you calling it "#9" and then "minor third", in the same sentence? Or is that a point about the interchangeability of the terms?