In Horace Silver’s own words ‘Senor Blues’ is a “low down, bluesy composition. A minor blues written in 6/8 time…a blues with a Latin beat added to it.” It’s a tough piece to play, especially for solo piano (to my knowledge Silver never recorded it without a horn section) but who doesn’t like a challenge?!
First off, ‘Senor Blues’ is in the key of Eb minor. Our analysis of ‘Nica’s Dream’ talks about how a minor key is arrived at (Link). There are six flats in the key which seems daunting but keep in mind everything is flat except the ‘f’ and the accidental.
It is not strictly a blues. I mention this for memorization purposes not to argue about what constitutes a blues. The form is I – VI – I – V – IV – I. The VI chord is written as B9 but it really is a Cb9.
Any chance we get to practice an ostinato bass pattern is time well spent. ‘Take Five’, ‘Linus and Lucy’ and countless others employ this “rub your stomach / pat your head” technique.
The importance of 6/8 time is discussed in our little primer of gospel music (Link).