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# How do you win rock-paper-scissors all the time? Here's the formula

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A new strategy for a successful winning streak in the age-old game of rock-paper-scissors is revealed and it is just as simple as one, two, three. Who knows, you might be the titleholder in the next Yahoo Rock Paper Scissors World Championships.
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When stuck in a dead end making decisions or just merely in a petty conundrum of who chooses which, people usually settle things with the age-old game of rock-paper-scissors. Though this game is tentatively dependent on chance, a new study suggests that you can actually turn the odds in your favor.

The new rock-paper-scissors “strategy” was revealed by a group of Zheijang University mathematicians in China, who were dubious if the game was affected by the popular game theory solution concept called “the Nash equilibrium.”  This principle implies that people will randomly choose each of the three options equally.

The concept was the brainchild of John Forbes Nash, Jr., an American mathematician whose life was eventually showed on the big screen in a movie entitle A Beautiful Mind.

The researchers’ findings solidified their doubts. Players were more inclined to play in a subtle but predictable pattern, which if players would only realize over time, could nail them a winning streak.

In the study, 360 students in their University were asked participate in the game of rock-paper-scissors. For 300 rounds at 90 to 150 minutes each, the players are randomly paired with the other participants, competing only once. For every game they won, the players were given incentives.

The results were satisfying. Players on a winning streak cast the same bets that made them win. On the other hand, those who kept losing changed their option in a ‘clockwise’ direction, from rock, to paper, to scissors, the researchers wrote. This was dubbed as the “win-stay lose-shift” strategy.

How does it work? Consider this example.

An opponent plays paper and the player lost because he or she played rock in the first round. The study suggests that in the next round, the player should play an option that would beat paper, which is scissors. After playing scissors and winning, the opponent may figure out that the player might be using scissors again because of the previous win. The opponent may try to use rock instead, which can then be countered with paper for another win.

Though rock-paper-scissors may be a simple game, but it is widely used by sociologists and biologists to learn more about the phenomenon of competition; be it for pricing systems in markets or diversity in ecosystems. Historical records show that the game dates back to the Han Dynasty, between 206 B.C. and 220 A.D. However, the first written reference to the game was found in a Chinese book during the 17th c1entury.

“Our theoretical calculations reveal that this new strategy may offer higher payoffs to individual players in comparison with the NE (Nash Equilibrium) mixed strategy, suggesting that high social efficiency is achievable through optimized conditional response,” the researchers wrote.

Simply put, winning a game of rock-paper scissors may simply require playing a hand that can beat the previous winning hand that a player lost against. The odds are that a previous winner will try playing the same hand that won the earlier round.