Where are the references to Ricardo in Paco's Soleá?
Given the title, I would expect there to be some. But I don't know Ricardo's work well enough to recognize them.
Outside of the basic traditional ideas por Arriba, Paco is simply acknowledging the maestro he learned so much from, yet has long since abandoned copying note by note. Generally speaking, those spots where he moves up to position 7 such as at 1:30 and 2:30 in the first video, have a lot of the flavor of Ricardo’s style. Keep in mind in Solea proper (for cante) we often capo so high that these types of passages are not practical and so a very Ricardo-soloist type of thing. Basically Ricardo was opening up the concept up high there as “por medio in transposition”, which today we take for granted but in his time was very innovative. At the same time Paco is not leaving out other influences such as Sabicas (those Bb chords in context) or Montoya (the open position ligados and the Caña ending).
