Rock-paper-scissors, also known as roshambo, has determined the outcome of millions of extremely important decisions. (That’s a rough estimate.) The knowledge that scissors cut paper, that rock ...

In 2007, one Jamie Langridge became $50,000 richer after winning intense national tournament in Las Vegas. Langridge beat his opponent decisively, with a classic open-hand technique. The sport?

Of all the decisions Cary Greif has made in her 38 years, this should have been among the simplest. “I had prepared. I had gone online and looked over strategies. But when I got up there, with the ...