At some point, you'll walk into a jam and ask yourself, "What key are they playing in?"
D. They're playing in D. Actually, all fiddle tunes are in D.
Actually, they're not. When I teach people how to identify wildflowers, I tell them that they can start out by calling every flower a dandelion. I say, "You'll be wrong a lot, but it'll give you the highest hit rate."
Traditional fiddle tunes are mostly in D, A, or G, in that order. Count on it. If you play a tune in C, it's probably from Mississippi. If you play a tune in F, it's obscure and from New England. If you play in E or B or G# or some other key, it's not a traditional fiddle tune.
I found myself on-stage, in Portland, Oregon, with Jack Falk, a klezmer clarinet player. "Do you know ...?" he asked, naming some-frelakhs-or-other. Of course not.
"What key is it in?" I asked.
"D," he said. "They're all in D."
