What Are Some Strategies for Winning "Rock Paper Scissors"?

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March 12 2013 2:17 PM

What Are Some Strategies for Winning "Rock Paper Scissors"?

A boy plays rock paper scissors with a humanoid robot in Tokyo.
A boy plays rock paper scissors with a humanoid robot in Tokyo.

Photo by Yoshikazu Tsuno/AFP/Getty Images

This question originally appeared on Quora.

Answer by Brad Fox, head referee, World Rock Paper Scissors Society:


Before anyone laughs, there is absolutely skill in the sport. If you look at the field for past world championships (which regularly draw more than 500 competitors) the same individuals keep making the top percentile year after year—clearly demonstrating skill can have a major effect on result.

1. Longer series matches increase the importance of skill and strategy.
There are few "single throw" strategies for RPS outside of some general demographic information (For North American English-speaking men, the most-to-least-common throws are Rock/Paper/Scissors — for North American English-speaking women, Rock/Scissors/Paper). Strategies don't really come into play beyond those broad strokes unless you're playing a series in which you can observe and react to you opponent over time. In the same vein, a veteran poker player would never have a strategy for only playing a single hand of cards. (The skill sets are very similar ... Phil Hellmuth, who has 13 WSOP bracelets, is an avid high-stakes RPS enthusiast.)

Many seasoned RPS players prefer to play "first to 10points" (aka "Hustler Style") although "first to 100" (aka "Century Matches") aren't uncommon when there is a lot of time available. World and national championship tournament matches are usually shorter but are still always series matches (usually best of 5 of 5—where one player must win 3 "best of 5" sets to take the match).

2. Control the tempo of the game instead of the patterns.
Reading and recognizing patterns on the fly requires a tremendous amount of skill. Priming (pumping your arm before delivering a throw) so fast your opponent doesn't have time to think of a strategy and defaults to "rock" does not. Playing a game so fast that your opponent doesn't have time to think (and defaults into very easily exploitable patterns) is known as "priming the chump." Conversely there are strategies about priming very slowly to get a frustrated opponent to declare their throw earlier than they need to. This technically isn't "cheating" as it can be done within the understood rules of the game (although not the game as most players tend to think of it, which is simply the resolution of the final declared throws).

3. Take advantage of the fact many players have no strategy.
This is absolutely not the same thing as playing "randomly." Humans are very, very bad at behaving truly randomly (the closest you can come in RPS play is to pre-memorize a string of randomly generated throws and not deviate from it ... but game theory suggests you have better odds playing an active strategy than a passive Nash equilibrium—since it's unlikely both players will have the same level of strategic understanding). For example: Most amateur players feel they need to change their throw each game in a series. This is the most powerful strategy against beginners that exists, if you recognize this behavior. (I'll leave it to the reader to figure out why, in a series game, this guarantees a loss if recognized by a savvy opponent. This is the basis of the "Roshambollah Gambit," which is pretty much the strategy used by most advanced players against people who don't believe skill has a part to play in RPS. It is very, very, effective).

4. Cheat.
There are several good ways to cheat in Rock Paper Scissors. While I certainly don't condone any of them, it's important for people to watch out for them, especially when playing in bars for money. (I don't know what it is about high level RPS players and hustling people in bars, but there seems to be a big overlap.) The major techniques include throwing late (not declaring a throw until after the opponent has ... usually indicated by a forearm "finishing" a throw at less than 45 degrees to the leg), throwing "turkey claw" (throwing a hand position that's not quite paper, not quite scissors and claiming the preferential throw), and abusing series play by not clearly agreeing to terms of the match until it's under way to adjust the length of the game based on the outcome of the first (or first few) decisions.

That last one is a particularly effective bar hustle, as a cheater can challenge someone to "rock, paper, scissors," claim victory if they win the first throw, and then continue on as if they always intended to play a "best of whatever" if they lose the first throw until the odds are in their favor (which they eventually will be the longer a series match goes).

5. Do More Research than the Other Player.
There are many good sources of advanced RPS strategy. A good starting point would be the Official Strategy Guide to Rock Paper Scissors by Douglas and Graham Walker.. While a little dated, and sometimes overly simplistic, there's a wealth of condensed information therein. (Disclosure: I have no involvement with or financial interest in this particular book, but the Walker brothers are the current interim heads of the World Rock Paper Scissors Society of which I'm an official and member).
 
6. Take Rock Paper Scissors Very, Very Seriously.
Don't be swayed by skeptics; Rock Paper Scissors is the oldest unmodified and widest-played sport in the entire world. With a little bit of effort, and study of non-transitive tripartite game theory, you'll never have to take out the garbage again—and the last piece of pizza will always be yours.

Yours in RPS,

BF (wrps)

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