Rock-paper-scissors chart |
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| Years active | Chinese Han Dynasty to present |
|---|---|
| Genre(s) | Hand game |
| Players | 2 |
| Setup time | None |
| Playing time | Instant |
| Random chance | High |
| Skill(s) required | Luck, psychology |
Rock-paper-scissors is a hand game played by two people. The game is also known as roshambo, or another ordering of the three items (with "stone" sometimes substituting for "rock").[1][2]
The game is often used as a choosing method in a way similar to coin flipping, drawing straws, or throwing dice. However, unlike truly random selection methods, rock-paper-scissors can be played with a degree of skill, especially if the game extends over many sessions with the same players; it is often possible to recognize and exploit the non-random behavior of an opponent.[3]
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Each of the three basic hand-signs (from left to right: rock, paper, and scissors) beats one of the other two, and loses to the other.
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The players count aloud to three, or speak the name of the game (e.g. "Rock Paper Scissors!" or "Ro! Cham! Beau!"), each time raising one hand in a fist and swinging it down on the count. After the third count (saying, "Scissors!" or "Beau!"), the players change their hands into one of three gestures, which they then "throw" by extending it towards their opponent. Variations include a version where players use a fourth count—"Shoot!"—before throwing their gesture, or a version where they only shake their hands twice before "throwing." The gestures are:
The objective is to select a gesture which defeats that of the opponent. Gestures are resolved as follows:
If both players choose the same gesture, the game is tied and the players throw again.
According to the Chinese Ming Dynasty writer Xie Zhaozhi's (谢肇淛) book Wuzazu (五杂组), the first known mention of the game, the game dates back to the time of the Chinese Han Dynasty (206 BCE – 220 CE),[4] it was called shoushiling (手势令). Li Rihua's (李日华) book Note of Liuyanzhai (六砚斋笔记) also reveals this game, calling it shoushiling (手势令), huozhitou (豁指头), or huoquan (豁拳).
In the 18th century these games were popular in Japan. It's known in Japan as Jan-ken-pon (じゃんけんぽん), more commonly called janken (じゃんけん) and sometimes called rock ken (石拳 ishiken). The origin or the derivation of the name is unknown. Ken (拳 ken) is a fist in Japanese and Jan-ken-po is categorized as a "ken (fist) games" (拳遊び ken asobi). Janken is believed to have been based on two older ken games, sū ken (数拳, number competing game with fingers, likely similar to or identical with Morra) and san sukumi ken (三すくみ拳, san sukumi means the freezing aspects of a snake, frog, and slug with fear). San sukumi ken has existed in Japan since ancient times, and sū ken was imported from China in the late 17th century; the name in China of sū ken is shǒushìlìng (手勢令). Ken games began to increase in popularity in the middle of the 19th century.
Rock-paper-scissors came to be played all over the world by the 20th century.
There is a simpler variation of the game, where instead of three possibilities, the game is just played with two possibilities. This version is called matching pennies, the two strategy equivalent to rock-paper-scissors.
Players have developed numerous cultural and personal variations on the game, from simply playing the same game with different objects, to expanding into more weapons and rules.
With an odd number of choices, each beats half the weapons and loses to half the weapons. No even number of weapons can be made balanced, unless some pairs of weapons result in a draw; there will always be some weapons superior to others.
An example of an unbalanced four-weapon game adds "dynamite" as a trump. Dynamite, expressed as the extended index finger or thumb, always defeats rock, and is defeated by scissors. Using dynamite generally implies that dynamite burns paper, but some claim that paper would smother the fuse. The fourth option of dynamite changes each gesture's odds of winning. For instance, scissors' odds improve from 33% to 50% while rock's odds decrease from 33% to 25%. Dynamite can be used to cheat by quickly raising or lowering the thumb on the downstroke once the opponent's play is recognized. Organized rock-paper-scissors contests never use dynamite.[7]
Similarly, the French game "pierre, papier, ciseaux, puits" (stone, paper, scissors, well) is unbalanced; both the rock and scissors fall in the well and lose to it, while paper covers both rock and well. This means two "weapons", well and paper, can defeat two moves, while the last two weapons can only defeat one of the other three choices.
One popular five-weapon expansion, invented by Sam Kass and Karen Bryla,[8] adds "Spock" and "lizard" to the standard three. "Spock" is signified with the Star Trek Vulcan salute, while "lizard" is shown by forming the hand into a sock-puppet-like mouth. Spock smashes scissors and vaporizes rock; he is poisoned by lizard and disproven by paper. Lizard poisons Spock and eats paper; it is crushed by rock and decapitated by scissors. This variant was mentioned in a 2005 article of The Times[9] and appeared in an episode of the sitcom The Big Bang Theory, "The Lizard-Spock Expansion," in 2008. As long as the number of moves is an odd number and that each move defeats exactly half of the other moves while being defeated by the other half, any combination of moves will function as a game. For example, 7, 9, 11, 15, 25 and 101 weapon versions exist[10] Adding new gestures has the effect of reducing the odds of a tie, while increasing the complexity of the game. The probability of a tie in a balanced, odd-weapon game can be calculated based on the number of weapons n as 1/n, so the probability of a tie is 1/3 in RPS, 1/5 in RPSLS and 1/101 in RPS101. It is possible to design balanced RPS games with an even number of weapons; unfortunately, this requires the introduction of ties. For instance, dynamite could be introduced such that dynamite defeats rock and paper defeats dynamite while rock and paper tie, as do scissors and dynamite. The probability of a tie in a balanced, even-weapon RPS game with n weapons (assuming each weapon ties with itself and only one other weapon, while defeating half of the remaining weapons and being beaten by the other half) can be calculated as 2/n, which essentially doubles the probability of a tie in comparison with odd-weapon RPS games.
In 2006, American federal judge Gregory Presnell from the Middle District of Florida ordered opposing sides in a lengthy court case to settle a trivial (but lengthily debated) point over the appropriate place for a deposition using the game of rock-paper-scissors.[11] The ruling in Avista Management v. Wausau Underwriters stated:
Upon consideration of the Motion – the latest in a series of Gordian knots that the parties have been unable to untangle without enlisting the assistance of the federal courts – it is ORDERED that said Motion is DENIED. Instead, the Court will fashion a new form of alternative dispute resolution, to wit: at 4:00 P.M. on Friday, June 30, 2006, counsel shall convene at a neutral site agreeable to both parties. If counsel cannot agree on a neutral site, they shall meet on the front steps of the Sam M. Gibbons U.S. Courthouse, 801 North Florida Ave., Tampa, Florida 33602. Each lawyer shall be entitled to be accompanied by one paralegal who shall act as an attendant and witness. At that time and location, counsel shall engage in one game of "rock, paper, scissors." The winner of this engagement shall be entitled to select the location for the 30(b)(6) deposition to be held somewhere in Hillsborough County during the period July 11–12, 2006.[12]
The public release of this judicial order, widely circulated among area lawyers, was seemingly intended to shame the respective law firms regarding their litigation conduct by settling the dispute in a farcical manner.
When Takashi Hashiyama, CEO of a Japanese television equipment manufacturer, decided to auction off the collection of impressionist paintings owned by his corporation, including works by Cézanne, Picasso, and van Gogh, he contacted two leading auction houses, Christie's International and Sotheby's Holdings, seeking their proposals on how they would bring the collection to the market as well as how they would maximize the profits from the sale. Both firms made elaborate proposals, but neither was persuasive enough to get Hashiyama’s business. Unwilling to split up the collection into separate auctions, Hashiyama asked the firms to decide between themselves who would hold the auction, which included Cézanne's "Large Trees Under the Jas de Bouffan", worth $12–16 million.
The houses were unable to reach a decision. Hashiyama told the two firms to play rock-paper-scissors to decide who would get the rights to the auction, explaining that "it probably looks strange to others, but I believe this is the best way to decide between two things which are equally good".
The auction houses had a weekend to come up with a choice of move. Christie's went to the 11-year-old twin daughters of the international director of Christie's Impressionist and Modern Art Department Nicholas Maclean, who suggested "scissors" because "Everybody expects you to choose 'rock'." Sotheby's said that they treated it as a game of chance and had no particular strategy for the game, but went with "paper".[14]
Christie's won the match and sold the twenty million dollar collection, with millions of dollars of commission for the auction house.
Japanese idol girl group AKB48 used in 2010 a rock-paper-scissors contest to determine which of the members would participate in a single. They used it again on September 20, 2011 with the contest being broadcast in four countries. The final winner was Mariko Shinoda.[15][16][17][18]
In many real-time strategy, first-person shooter, and role-playing video games, it is common for a group of possible weapons or unit types to interact in a rock-paper-scissors style, where each selection is strong against a particular choice, but weak against another, emulating the cycles in real world warfare (such as cavalry being strong against archers, archers being strong against pikemen, and pikemen being strong against cavalry[19]). Such game mechanics can make a game somewhat self-balancing, and prevent gameplay from being overwhelmed by a single dominant strategy.[19]
Many card-based video games in Japan use the rock-paper-scissors system as their core fighting system, with the winner of each round being able to carry out their designated attack. Other games use simple variants of rock-paper-scissors as subgames.
The common side-blotched lizard (Uta stansburiana) exhibits a rock-paper-scissors pattern in its mating strategies. Of its three color types of males, "orange beats blue, blue beats yellow, and yellow beats orange" in competition for females, which is similar to the rules of rock-paper-scissors.[20][21]
Some bacteria also exhibit a rock-paper-scissors dynamic when they engage in antibiotic production. The theory for this finding was demonstrated by computer simulation and in the laboratory by Benjamin Kerr, working at Stanford University with Brendan Bohannan.[22] The antibiotics in question are the bacteriocins - more specifically, colicins produced by Escherichia coli. Biologist Benjamin C. Kirkup, Jr. further demonstrated that the colicins were active as E. coli compete with each other in the intestines of mice, and that the rock-paper-scissors dynamics allowed for the continued competition among strains: antibiotic-producers defeat antibiotic-sensitives; antibiotic-resisters multiply and withstand and out-compete the antibiotic-producers, letting antibiotic-sensitives multiply and out-compete others; until antibiotic-producers multiply again.[23]
It is easy to see that it is impossible to gain an advantage over a truly random opponent. However, by exploiting the weaknesses of nonrandom opponents, it is possible to gain a significant advantage.[24] Indeed, human players tend to be nonrandom.[25] As such, there have been programming competitions for algorithms that play rock-paper-scissors.[24][26][27]
As a consequence of rock-paper-scissors programming contests, many strong algorithms have emerged.[24][26][27] For example, Iocaine Powder, which won the First International RoShamBo Programming Competition in 1999,[26] uses a heuristically designed compilation of strategies.[28] For each strategy it employs, it also has six metastrategies which defeat second-guessing, triple-guessing, as well as second-guessing the opponent, and so on. The optimal strategy or metastrategy is chosen based on past performance. The main strategies it employs are history matching, frequency analysis, and random guessing. Its strongest strategy, history matching, searches for a sequence in the past that matches the last few moves in order to predict the next move of the algorithm. In frequency analysis, the program simply identifies the most frequently played move. The random guess is a fallback method that is used to prevent a devastating loss in the event that the other strategies fail. More than ten years later, the top performing strategies on an ongoing rock-paper-scissors programming competition similarly use metastrategies.[29] However, there have been some innovations, such as using multiple history matching schemes that each match a different aspect of the history - for example, the opponent's moves, the program's own moves, or a combination of both.[29] There have also been other algorithms based on Markov chains.[30]
Starting in 2002, the World Rock Paper Scissors Society standardized a set of rules for international play[31] and has overseen annual International World Championships. These open, competitive championships have been widely attended by players from around the world and have attracted widespread international media attention.[32][33][34][35][36] WRPS events are noted for their large cash prizes, elaborate staging, and colorful competitors.[37] In 2004, the championships were broadcast on the U.S. television network Fox Sports Net, with the winner being Lee Rammage, who went on to compete in at least one subsequent championship.[38][39]
| Year | World Champion | Country |
|---|---|---|
| 2002 | Peter Lovering | Canada |
| 2003 | Rob Krueger | Canada |
| 2004 | Lee Rammage | Canada |
| 2005 | Andrew Bergel | Canada |
| 2006 | Bob Cooper | United Kingdom |
| 2007 | Andrea Farina[40] | USA |
| 2008 | Monica Martinez | Canada |
| 2009 | Tim Conrad | USA |
USA Rock Paper Scissors League is a US-based rock-paper-scissors league. It is sponsored by Bud Light. Leo Bryan Pacis is the commissioner of the USARPS.
In April 2006, the inaugural USARPS Championship was held in Las Vegas. Following months of regional qualifying tournaments held across the US, 257 players were flown to Las Vegas for a single-elimination tournament at the House of Blues where the winner received $50,000. The tournament was shown on the A&E Network on June 12, 2006.
The $50,000 2007 USARPS Tournament took place at the Las Vegas Mandalay Bay in May 2007.
In 2008, Sean "Wicked Fingers" Sears beat out 300 other contestants and walked out of the Mandalay Bay Hotel & Casino with $50,000 after defeating Julie "Bulldog" Crossley in the finals.
The inaugural Budweiser International Rock, Paper, Scissors Federation Championship was held in Beijing, China after the close of the 2008 Summer Olympic Games at Club Bud. A Belfast man won the competition.[41] Sean finished 3rd.
The XtremeRPS National Competition[42] is a US nationwide RPS competition with Preliminary Qualifying contests that started in January 2007 and ended in May 2008, followed by regional finals in June and July 2008. The national finals were to be held in Des Moines, Iowa in August 2008, with a chance to win up to $5,000.
The 1st UK Championship took place on July 13, 2007, and then again on July 14, 2008, in Rhayader, Powys. Steve Frost of Powys is the current holder of this WRPS sanctioned event.
The 3rd UK Championships took place on June 9, 2009, in Exeter, Devon. Nick Hemley, from Woking, Surrey, won the contest just beating Chris Grimwood.[43]
The 4th UK Championships took place on November 13, 2010, at the Durell Arms in West London. Paul Lewis from Woking beat Ed Blake in the final and collected the £100 first prize and UK title. Richard Daynes Appreciation Society won the team event. 80 competitors took part in the main contest and 10 entries in the team contest.
The 5th UK Rock Paper Scissors Championships took place in London on Saturday 22 October 2011.[44] The event was open to 256 competitors. There is also a team contest. The 2011 singles tournament was won by Max Deeley and the team contest won by The Big Faces (Andrew Bladon, Jamie Burland, Tom Wilkinson and Captain Joe Kenny).[45]
On April 3, 2009, Colonel By Secondary School in Ottawa, Canada, held the largest recorded rock-paper-scissors tournament, with approximately 1150 participants. The contest was throughout all the Grade 9-12s, and included teachers. The winner, Cody Lombardo, took home a trophy, and had his name in the Guinness Book of World Records.[46]
On July 9, 2010, over 6500 attendees of the LIFE 2010 Conference in Louisville, Kentucky, participated in the largest tournament of Rock-Paper-Scissors ever, shattering the previous record of 1150 participants.
Former Celebrity Poker Showdown host and USARPS Head Referee[47] Phil Gordon has hosted an annual $500 World Series of Rock Paper Scissors event in conjunction with the World Series of Poker since 2005.[48] The winner of the WSORPS receives an entry into the WSOP Main Event. The event is an annual fundraiser for the "Cancer Research and Prevention Foundation" via Gordon's charity Bad Beat on Cancer. Poker player Annie Duke won the Second Annual World Series of Rock Paper Scissors.[49][50] The tournament is taped by ESPN and highlights are covered during "The Nuts" section of ESPN's annual WSOP broadcast.[51][52][53] 2009 was the fifth year of the tournament.
The Red Bull Roshambull is a Recognized Unofficial event by the World RPS which takes place over the Facebook application "Red Bull Roshambull". Although originally an unrecognized event, in January 2011 it was given a Official Recognized event status due to the number of people who regularly take part in the World Championships and other recognized leagues starting to compete. However the event is still seen as a non-ranking event and any awards or titles given in the tournament are not officially recognized outside the event.
The World Series is a multiple-tournament contest in which a player's performance in each separate tournament is scored, and after a number of tournaments within the event have taken place, a triple-elimination playoff takes place to decide a overall championship. Over the last few seasons, extra events have been added to the series, the most popular of them being the "Hidden Stars" (a tournament for novice players on the application who may not know about the event being given a chance to compete without any regulars taking part) and the World Series Blitz (where all the events take place over one day rather than once a week like in the main event).
The key feature of this event is the number of players who are not known as people who play in real-life tournaments who show a lot of ambition to try to compete with those who play in the most recognized events on a regular basis. This has created a small community of players as well as a small rivalry between both sets of players to prove who is better.
The Tournament was wound up in 2012 after Red Bull's support for the application was withdrawn, and Facebook's change of coding meant that the application was forced to be removed. The World RPS along with the Hardcore fans of the game have started discussing with the people who helped Red Bull run the game about recreating the application under a new name due to the games popular demand from the regular users of the game.
| Season | Overall result | League phase | Hidden Stars | World Series Blitz | World Team Challenge |
|---|---|---|---|---|---|
| Summer 2009 | 1ST Alan Giles 2nd Mark Thomas |
1ST Mark Thomas 2nd Monika Hjelmas |
Not Competed in This season | ||
| Winter 2009/10 | 1ST Frances Anne Ricketts 2nd Mark Thomas |
1ST Frances Anne Ricketts 2nd Clayton Dwyer |
Not Competed in This season | ||
| Summer 2010 | 1ST Brett McFarlane 2nd Tom Bussineau |
1ST Andrew Lampman 2nd Brett McFarlane |
1ST Lex Harrison 2nd Jaden Urquhart |
Not Competed in this season | 1ST Norway Erik Westnes, Anna Kvalheim, Monika Hjelmas 2nd African Nations Mac Anamourlis, Craig Von Hagen, Jakqui Krobo |
| Winter 2010/11 | 1ST Richard Morgan 2nd Andrew Lampman |
1ST Carol Lampman 2nd Andrew Lampman |
1ST Amanda Parsons 2nd Leona Colton |
1ST Andrew Lampman 2nd Carol Lampman |
Not competed in this season |
| 2011 (Changed to calendar year seasons) | Not yet started | 1ST Andrew Lampman 2nd Nikki Montoya |
Not Held this year | 1ST Andrew Lampman 2nd Carol Lampman |
1ST USA Tom Bussineau, Mark Thomas, Mark Tuden 2nd Norway Erik Westnes, Anna Kvalheim, Monika Hjelmas |
In December 2010, a player called Maxamillion Air became one of the first online-only players from the World Series to play in an official event.
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