More details on the Robert Johnson crossroads transaction:
“If you want to learn how to play anything you want to play and learn how to make songs yourself, you take your guitar and you go to where a road crosses that way, where a crossroad is. Get there, be sure to get there just a little 'fore 12:00 that night so you’ll know you’ll be there. You have your guitar and be playing a piece there by yourself… A big black man will walk up there and take your guitar, and he’ll tune it. And then he’ll play a piece and hand it back to you. That’s the way I learned to play anything I want.”
Not a direct quote from RJ, but from Tommy Johnson, another Mississippi bluesman familiar with the lore, as quoted in the book Searching for Robert Johnson by Peter Guralnick
Strangely similar to Fretful Propentine’s quote, isn’t it?