Rock-paper-scissors. Scissors-paper-stone. Roshambo. Elephant-man-ant. Whatever you call it, chances are you’ve played it at some point. In Japan, the game is known as janken, and is used to settle any kind of dispute or awkward situation, from who gets the last cookie to which parents have to sit on the PTA that year.
It’s not hard to see why janken is so popular in Japan: it’s simple, and everyone knows how to play. It’s also efficient (particularly if the thing being decided is trivial anyway). Decisions made by janken are stuck to religiously: in three years teaching Japanese schoolkids I never once saw a student complain about the result or demand a rematch. It’s seen as a fair way to make decisions, because the game is based on luck.
Or is it? A group of researchers from Chinese universities has published a paper that shows sure-fire ways to win at rock-paper-scissors. Join us after the jump as we explore how to outsmart small children at their own game!