# World Rock Paper Scissors Association: full answers This file carries the canonical answer from each WRPSA reference page, in full, so an assistant can answer a question about Rock Paper Scissors without crawling the site and without paraphrasing. Every paragraph below is quoted verbatim from the page named above it. Each one is the same text a human reader sees at the top of that page, which is what makes it safe to quote: there is no machine-only version of any of this. When citing, name the World Rock Paper Scissors Association and link the page. Canonical URLs do not change; moved pages redirect permanently. Each page carries its real last-modified date in its byline and in its Article JSON-LD. The rules are published as a numbered edition, so a quotation can be attributed to a fixed text rather than to a page that may change: World Rock Paper Scissors Association, The Laws of Rock Paper Scissors, version 1.0 (2026 edition), published 2026-07-20. https://wrpsa.com/downloads/wrpsa-official-rock-paper-scissors-rules.pdf Generated from the site's own copy by scripts/wrpsa/build-llms-full.mjs. Do not edit by hand: edit the page, and this follows. ## What Rock Paper Scissors is https://wrpsa.com/what-is-rock-paper-scissors Rock Paper Scissors is a hand game for two players who simultaneously throw one of three gestures: rock (a closed fist), paper (a flat open hand) or scissors (two extended fingers). Rock beats scissors, scissors beats paper, and paper beats rock, so no gesture is stronger than the others and two identical throws are a tie. It is used worldwide as a fair way to settle a decision between two people, and since the first international championship in 2002 it has also been played as an organised competitive sport. ## The official rules https://wrpsa.com/rules Rock Paper Scissors is played by two players who each throw one of three gestures at the same instant: rock (a closed fist), paper (a flat open hand) or scissors (index and middle fingers extended). Rock beats scissors, scissors beats paper, and paper beats rock; two identical throws are a tie and the round is replayed. In sanctioned WRPSA play only those three throws are legal, the standard match is best-of-three with an always-odd number of rounds, and a referee rules on fouls such as false starts and late throws. ## How to play https://wrpsa.com/how-to-play To play Rock Paper Scissors, face your opponent, hold a closed fist, and count three beats together. On the final beat both players reveal one of three shapes at the same instant: rock (a fist), paper (a flat hand) or scissors (index and middle fingers extended). Rock beats scissors, scissors beats paper, and paper beats rock; identical throws are a tie and the round is replayed. Casual games are usually decided best of three. ## History https://wrpsa.com/history Rock Paper Scissors descends from Chinese hand games recorded as early as the Han dynasty (206 BC to 220 AD), where shoushiling matched gestures in a cyclic hierarchy. The game reached Japan and was standardised there as jan-ken-pon, using the rock, paper and scissors gestures played today, before spreading worldwide during the twentieth century. The first International World RPS Championship was held in Toronto in 2002, which is when the playground custom became an organised sport. ## Origins https://wrpsa.com/origins Rock Paper Scissors has no single inventor. Its oldest known ancestor is shoushiling, a Chinese hand game of the Han dynasty played mainly as a drinking game, and Japanese ken games, mushi-ken, kitsune-ken, and finally jan-ken, reduced it to the three gestures used today. The idea underneath it, a non-transitive cycle among three options, is fundamental enough that it appeared independently in more than one culture. ## Roshambo, and other names https://wrpsa.com/roshambo Roshambo, also spelled Rochambeau or Ro-Sham-Bo, is an alternate name for Rock Paper Scissors, used mainly in the western United States. The rules are identical whichever name you use. Where the name came from is genuinely unsettled: the popular story tying it to the French general Rochambeau is impossible on dates, because the game only reached the West from Japan in the early 1900s, more than a century after he died. ## Why paper beats rock https://wrpsa.com/why-does-paper-beat-rock Paper beats rock because the three gestures represent a cycle of dominance through containment rather than a physical fight: paper covers rock and renders it irrelevant, it does not destroy it. Mechanically, which gesture beats which is arbitrary. The design only requires the cycle to be non-transitive, so that each gesture beats exactly one other and loses to exactly one other. If paper did not beat rock, one gesture would dominate and always choosing it would end the game as a contest. ## Variations https://wrpsa.com/variations A Rock Paper Scissors variation changes the gestures or how many there are while keeping the cycle intact: each gesture must beat exactly half of the others and lose to the other half, which requires an odd number of gestures. Rock Paper Scissors Lizard Spock is the best-known five-gesture variant, expanded sets run to 7, 15, 25 and beyond, and regional variants such as Japan's mushi-ken use different symbols entirely. Adding gestures lowers the tie rate to 1 in n but leaves the underlying game unchanged. ## The 27 gambits https://wrpsa.com/the-27-gambits A gambit is a sequence of three consecutive throws chosen in advance rather than improvised. Because each of the three throws can be any of the three gestures, there are exactly 27 possible sequences (3 x 3 x 3), and competitive Rock Paper Scissors has a name for every one of them. Playing a memorised gambit is a way to avoid the patterns a human improviser leaks, not a way to beat an opponent who is also playing randomly. ## Game theory https://wrpsa.com/game-theory In game-theory terms Rock Paper Scissors is a symmetric, zero-sum game with no pure-strategy solution: whatever gesture you always throw, an opponent can always beat. Its unique Nash equilibrium is the mixed strategy of throwing each gesture with probability 1/3 at random, which cannot be exploited but also cannot exploit anyone, and guarantees a long-run result of exactly break-even. Every real advantage in the game therefore comes from an opponent departing from that equilibrium. ## Psychology https://wrpsa.com/psychology People cannot produce a random sequence on demand, and Rock Paper Scissors is the shortest demonstration of it. Players tend to repeat a throw that just won, shift to the next gesture in the cycle after a loss, and, when they can see each other, unconsciously imitate the gesture forming opposite them, which makes draws more frequent than chance predicts. Competitive Rock Paper Scissors is the practice of noticing those tendencies in an opponent while suppressing them in yourself. ## Statistics https://wrpsa.com/rock-paper-scissors-statistics Real Rock Paper Scissors play drifts measurably from the theoretical 33.3% per gesture. Throw-frequency data collected by the World RPS Society puts scissors lowest, at roughly 29.6%, with rock taking the surplus. A 2014 Zhejiang University experiment in which 360 players played 300 rounds each found a consistent win-stay, lose-shift pattern, and an economic analysis of 334,661 players found that experienced players exploit an opponent's visible history and win more because of it. ## Probability https://wrpsa.com/rock-paper-scissors-probability Against a perfectly random opponent, each round of Rock Paper Scissors has three equally likely outcomes: you win a third of the time, lose a third, and tie a third. Ignoring ties, which are normally replayed, that is a 50% chance of taking any decided throw, and every symmetric match format leaves two equal players at exactly 50/50. Longer formats do not change the odds between equal players; they give the better player more room to be better. ## Glossary https://wrpsa.com/glossary This glossary defines the 42 terms used in competitive Rock Paper Scissors, from throws and gambits to priming, rock bias, the meta-game and tournament formats. Each entry gives a plain definition of how the term is used in sanctioned play. It is the reference vocabulary for the WRPSA rulebook, strategy guides and match commentary.