Distinguished SOTW Member, Forum Contributor 2017
Yup...Even with a stage full of players who've never met, you can play some surprisingly good blues with some simple instructions...You could start by asking them what key the tune is in. Eventually you'll be able to figure out the key by hearing the tonal center..snip....
I've worked with several band leaders who would turn to the band and say something like, "Jump in Bb", or "Backwards shuffle in G".
That's enough to have the right players cooking from note one...