@charlietranpiano: Beyond the scales... the chords... the tunes... We still need to consider the physical aspect of playing jazz. Downward leaps are such a common element of jazz language, but it certainly isn't something that happens naturally for most of us. I had to really drill this skill so I could nail those bebop lines that constantly leap in both directions - the skill of preparing the right finger for the note immediately before the leap, so that my hand was free to leap downward onto my thumb. You'll be using the weaker fingers 4 and 5 a whole lot more in order to accomplish, and they'll be better coordinated as a result.