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==General Strategies==
==General Strategies==
Strategy between human players obviously involves using psychology to attempt to predict or influence opponent behavior. It is considered acceptable to use deceptive speech (e.g. "Good old Rock, nothing beats rock!", A quote from [[The Simpsons]], or "Nah, Rock flies right through Paper!", a quote from [[Seinfeld]]) to influence one's opponent.
Strategy between human players obviously involves using psychology to attempt to predict or influence opponent behavior. It is considered acceptable to use deceptive speech (e.g. "Good old Rock, nothing beats that!", A quote from [[The Simpsons]], or "Nah, Rock flies right through Paper!", a quote from [[Seinfeld]]) to influence one's opponent.


Mathematically optimal play (according to [[game theory]]) is a simple matter of selecting randomly, and so the game may be considered trivial in that sense when played in a way that eliminates psychology, as with a computer program that does not take into account previous throws. But "optimal" in this sense means only "incapable of being defeated more than expected by chance", while it does ''not'' imply that the random strategy is best at taking advantage of a suboptimal opponent. In fact, if the opponent is human or a non-random program, it is almost certain that he plays suboptimally and that a modified strategy can exploit that weakness. This is easily demonstrated by [[Roshambot]], a computer program that easily defeats some human players (as does its author [[Perry Friedman]], who won an $800 competition against seven opponents including former world poker champion [[Phil Hellmuth]] in August 2001). [[Poker]] player Darse Billings of the [[University of Alberta]] organizes a computer Rock-Paper-Scissors competition to explore these possibilities, and their application to computer game play in other fields (notably poker, in which exploiting an opponent's non-random behavior is an important part of strategy).
Mathematically optimal play (according to [[game theory]]) is a simple matter of selecting randomly, and so the game may be considered trivial in that sense when played in a way that eliminates psychology, as with a computer program that does not take into account previous throws. But "optimal" in this sense means only "incapable of being defeated more than expected by chance", while it does ''not'' imply that the random strategy is best at taking advantage of a suboptimal opponent. In fact, if the opponent is human or a non-random program, it is almost certain that he plays suboptimally and that a modified strategy can exploit that weakness. This is easily demonstrated by [[Roshambot]], a computer program that easily defeats some human players (as does its author [[Perry Friedman]], who won an $800 competition against seven opponents including former world poker champion [[Phil Hellmuth]] in August 2001). [[Poker]] player Darse Billings of the [[University of Alberta]] organizes a computer Rock-Paper-Scissors competition to explore these possibilities, and their application to computer game play in other fields (notably poker, in which exploiting an opponent's non-random behavior is an important part of strategy).

Revision as of 04:49, 10 August 2006

For the Catatonia album, see Paper Scissors Stone (album).
Rock, Paper, Scissors chart
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Rock, Paper, Scissors, also known in Japan as Janken, is a hand game most often played by children. It is often used as a selection method in a similar way to coin flipping, Odd or Even, throwing dice or drawing straws to randomly select a person for some purpose, though unlike truly random selections it can be played with skill if the game extends over many sessions, because one can often recognize and exploit the non-random behavior of an opponent.

Various sports may use Rock, Paper, Scissors to determine which team gets the opening play (rather than a coin toss). Similarly, uncertain calls, or even the whole game in case of rain, may be decided by the game. It is also often used as a method for creating appropriately non-biased random results in live action role-playing games, as it requires no equipment.

Game play

Each of the three basic hand-signs ( from left to right: rock, paper and scissors ) beats one of the other two.

The players count together to 3 counts, most commonly either using the name of the game (e.g. Rock! Paper! Scissors! or Ro! Sham! Bo!) or simply numbers. At the end of the third count, the players simultaneously change their fists into any of three "objects", which they then "throw" by extending it towards their opponent:

  • Rock: a clenched fist.
  • Paper : all fingers extended, palm facing downwards, upwards, or sideways.
  • Scissors: forefinger and middle finger extended and separated into a "V" shape.

The objective is to defeat the opponent by selecting a weapon which defeats their choice under the following rules:

  1. Rock smashes (or breaks or blunts) Scissors (rock wins)

if in overtime middle fingers ARE allowed

  1. Scissors cut Paper (scissors win)
  2. Paper covers Rock (paper wins)

If players choose the same weapon, the game is a tie and is played again.

In International competition, the weapon is thrown on the fourth count ("1 ... 2 ... 3 ... THROW"). This is called "International Style." In "American Style," the throw comes on the third count ("1 ... 2 ... THROW").

Typically, the game is played in a "best 2 out of 3" match.

Japanese Gameplay

While in essence the same game, the Japanese version, known as Janken, varies slightly.

  • clenched fist: is called gu
  • flat hand : is called pa
  • two-finger V-shape: is called choki

The game begins with both players simultaneously saying the phrase "saisho wa gu", meaning "first is fist" and extending a gu hand to signal the start of the exchange. Then both players slowly pull back their hands while saying "jan ken..." and then on the word "poi" or "pon" (the final word varies by region) "throw" either gu, pa, or choki. The relationships between the three possible throws are the same as in most other versions of the game in other parts of the world.

Should both players make the same throw, the players say "aiko desho" (meaning "it's a tie") and on desho, make another throw. This can be repeated for unlimited ties, should they occur in sequence.

General Strategies

Strategy between human players obviously involves using psychology to attempt to predict or influence opponent behavior. It is considered acceptable to use deceptive speech (e.g. "Good old Rock, nothing beats that!", A quote from The Simpsons, or "Nah, Rock flies right through Paper!", a quote from Seinfeld) to influence one's opponent.

Mathematically optimal play (according to game theory) is a simple matter of selecting randomly, and so the game may be considered trivial in that sense when played in a way that eliminates psychology, as with a computer program that does not take into account previous throws. But "optimal" in this sense means only "incapable of being defeated more than expected by chance", while it does not imply that the random strategy is best at taking advantage of a suboptimal opponent. In fact, if the opponent is human or a non-random program, it is almost certain that he plays suboptimally and that a modified strategy can exploit that weakness. This is easily demonstrated by Roshambot, a computer program that easily defeats some human players (as does its author Perry Friedman, who won an $800 competition against seven opponents including former world poker champion Phil Hellmuth in August 2001). Poker player Darse Billings of the University of Alberta organizes a computer Rock-Paper-Scissors competition to explore these possibilities, and their application to computer game play in other fields (notably poker, in which exploiting an opponent's non-random behavior is an important part of strategy).

One high-profile strategic opinion came in 2005 from Alice Maclean, age 11. When rival auction houses Christie's and Sotheby's agreed to play rock-paper-scissors to determine the rights to a highly valuable art collection, Maclean's father Nicholas, a Christie's employee, asked her for advice. As later told to reporters, her strategy was summed up thus: "Everybody knows you always start with scissors. Rock is way too obvious, and scissors beats paper." (Christie's won, with scissors.)[1]

Cheating

One of the first tricks learned by a Rock-Paper-Scissors novice is to hold back a throw of paper until the last possible moment to dupe an opponent into believing that one may actually be throwing a rock. Both paper and scissors have this ability; however, unless one is employing a "double-back" strategy, cloaking a paper throw is likely to draw an instinctive paper from one's opponent.

A common variation on the opening ritual is to have both players hold their hands behind their backs and reveal their already formed throw after the count of three. The intention is to prevent any sort of timing based cheating.

Variations

See Rock, Paper, Scissors variations

There are many different variations of Rock, Paper, Scissors which range from simple changes in the names of the objects to increasing the number of players or objects. While interesting, most rule variations suffer from one problem or another, making them less interesting games. Versions of this game are also observed in many different cultures. It is usually known by direct translations of "Rock, Paper, Scissors" although some cultures have slightly different names or even entirely different elements representing the different objects. For example in Japan there is a variation which uses a tiger, a chief and the chief's mother as the three elements (the tiger beating the chief's mother, the chief beating the tiger and the chief's mother beating the chief). In Indonesia another version is played with the elements as an elephant, a man and an ant (the elephant crushing the man, the man crushing the ant and ant humorously defeating the elephant by crawling into the animal's ear and making it go insane)[1]. The Chinese and Koreans use Cloth along with Rock and Scissors, while the Japanese have adopted Paper.[2] Minor variation is also observed in the standard game play.

Another variation is known as RPS-25[2] from umop.com, which is an extreme version of the classic game with 25 different gestures instead of just three.

The additions are: Gun, Dynamite, Nuke, Devil, Boot, Dragon, Alien, Water, Bowl, Air, Moon, Sponge, Wolf, Cockroach, Tree, Man, Woman, Monkey, Snake, Axe, Fire, and Sun.

There is a very complex set of relationships between these gestures, which almost require a chart to play. Simpler variations include RPS-7,[3] RPS-9,[4] RPS-11,[5] and RPS-15.[6]

A very popular variation is "Rock, Paper, Scissors, Slap". Two people are locked in a perpetual handshake. When Person A wins, Person A turns the hands so Person B's hand is facing up. Person A then slaps Person B's hand.

Richard Bartle invented a game Spellbinder in 1977, which may be considered as a quite successful variation of Rock, Paper, Scissors.

Multiplayer RPS

When playing with more than two people, all players throw simultaneously. If all three objects are displayed, there is no winner and the game is repeated with all players. If only two symbols are displayed (e.g. half of the players threw paper and half threw scissors), the players showing the losing object are out of the game, and it is repeated with the remaining players until only one winner remains. This is a common method of selecting a starting player among devotees of German-style board games.

Extreme RPS

Extreme RPS uses the same rules as regular RPS except that the winning "weapon" is used to attack the losing player. If you pick rock and lose to paper you get a slap on the upper arm. If you pick paper and lose to scissors you receive a "stinger" on the inside of the elbow where the veins usually come to the surface. A stinger is when you slap with the index and middle fingers. If you pick scissors and lose to rock you get a punch on the upper arm.

Math and non-transitivity

Rock, Paper, Scissors is also often used as an example of the mathematical concept of non-transitivity. A transitive relation R is one for which a R b and b R c implies a R c. A reflexive, antisymmetric, and transitive relation on a set is known as a partial ordering, from which notions of "greater" and "less" follow. A game option which is "greater" than another is closer to being optimal, but such a notion does not exist in Rock, Paper, Scissors: The relation used to determine which throws defeat which is non-transitive. Rock defeats Scissors, and Scissors defeat Paper, but Rock loses to Paper. In fact, Rock-Paper- Scissors could be called "antitransitive" because if A strictly defeats B, and B strictly defeats C, A necessarily loses against C.

History

There are several different popular theories regarding the origin of Rock, Paper, Scissors. The so-called "Asian Theory" states that the game originated in Japan under the name of Jan ken perhaps as early as 200 B.C.E.. It is believed that with increased contact between eastern and western civilizations the game spread to Europe in the mid 1700s. Some speculate that during this time Rock, Paper, Scissors became inexplicably associated with Jean Baptiste Donatien de Vimeur, Comte de Rochambeau giving rise to the game's alternative western name Rochambeau or the more commonly spelled Roshambo. The "African Theory", similar to the "Asian Theory", relies on early development of tools by humans in the region. The "European Theory" contests that the game either started as a Scandinavian pastime which eventually spread to the rest of the continent or was brought by Celtic tribes to Portugal, with time reaching the remainder of Europe. One member of the World RPS Society's website who goes by the name "Joao V de Portugal" states: "Current research undertaken at the University of Lisbon by Baltasar Rui Delfim, soon to be published in Nature and Time, has shown that the origins of the game of Paper, Scissors and Rock (Pihedra, Papelsh e Tijhera) can be attributed to Celtic settlers in the northern regions of Portugal, near the Portuguese/Spanish border, around the 6th century BC. . . . It is believed that the game spread to the rest of Portugal in the 3rd century BC and to the rest of the Spanish peninsula over the next 50 years. Roman invasion of Hispania in the 1st century AD made the game popular in Gallia and Italia." The user then makes the somewhat difficult to believe and so far unsubstantiated claim that "...the Romans did not introduce the game to the UK because they believed that the game could make the UK colonies rebel against the Senate and it was not until the Portuguese armada of 350 AD came to England that the game was properly introduced in Britannia." [3]

Pop culture trivia

Main article: List of pop culture references to Rock, Paper, Scissors

Because of its widespread use by children and adults, Rock Paper Scissors has received substantial references in popular culture. Seinfeld, The Simpsons, and That 70s Show all poke fun at particular characters' incompetence at understanding the game rules. In other shows, mischievous characters are often able to "win" the game by deploying new objects which beat all the others and are subsequently able to convince their slow-witted competitor that deploying the new object is a legitimate move. In video games, intransitive relationships (like Rock, Paper, Scissors) often appear either in strategy choices or in weapons' abilities.

"Rock is Dead. Long live Paper and Scissors." is a popular t-shirt among young people wishing to express disdain for the lack of quality rock music available.

Federal case

In 2006, 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. He ruled in Avista Management v. Wausau Underwriters:

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 (1) 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.[7]

Evolutionary strategy

The Common Side-blotched Lizard (Uta stansburiana) exhibits a Rock-Paper-Scissors pattern in its mating behaviour evolutionary strategy.

Biologist Barry Sinervo from the University of California, Santa Cruz has discovered a Rock-Paper-Scissors evolutionary strategy in the mating behaviour of the side-blotched lizard species Uta stansburiana. Males have either orange, blue or yellow throats and each type follows a fixed, heritable mating strategy:[8]

  • Orange-throated males are strongest and do not form strong pair bonds; instead, they fight orange-throated males for their females. Yellow-throated males, however, manage to snatch females away from them for mating.
  • Yellow-throated males are smallest, and their coloration mimicks females. Under this disguise, they can approach orange-throated males but not the stronger-bonding blue-throated specimens and mate while the orange-throats are engaged in fights.
  • Blue-throated males are middle-sized and form strong pair bonds. While they are outcompeted by orange-throated males, they can defend against yellow-throated ones.

The proportion of each male type in a population is similar in the long run, but fluctuates heavily in the short term. For periods of 4-5 years, one strategy predominates, after which it declines in frequency as the strategy that manages to exploit its weakness increases. This corresponds to the stable pattern of the game in the replicator dynamics where the dynamical system follows closed orbits around the mixed strategy Nash equilibrium.

Tournaments

WRPS Sanctioned Tournaments

Starting in 2002, the World Rock Paper Scissors Society (WRPS) standardized a set of rules for international play [9] 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.[10][11][12][13][14][15] WRPS events are noted for their large cash prizes, elaborate staging, and colourful competitors.[16] In 2004, the championships were broadcast on the U.S. television network Fox Sports Net.

Professional poker player Phil Gordon conducted what he called "The World Series of Rock-Paper-Scissors" during the 2005 World Series of Poker in which 64 contestents of the WSOP competed in a tournament similar to the NCAA tournament.

World Championship results since 2002

Year Host City Medal Champion Gender Nationality
2002 Toronto Gold Peter Lovering Male Canadian
Silver Moe Asem Male Canadian
Bronze Dave Ferris Male Canadian
2003 Gold Rob Krueger Male Canadian
Silver Marc Rigaux Male Canadian
Bronze Patrick Merry Male Canadian
2004 Gold Lee Rammage Male Canadian
Silver Heather Birrell Female Canadian
Bronze Chris Berggeren Male American
2005 Gold Andrew Bergel Male Canadian
Silver Stan Long Male American
Bronze Stewart Waldman Male American

Tour events

In addition to the International World Championships the WRPS also endorses or sanctions a year-round series of tournaments world wide. "Endorsed" tournaments agree to abide by the WRPS standardized international rules of play and code of conduct, while "Sanctioned" tournaments will net the winner a trip to compete at the International World Championships. Some of the major events of this tour include:

USARPS Tournaments

In April 2006, the inaugural USA Rock Paper Scissors League Championship was held in Las Vegas, Nevada.[17] 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 aired on A&E on June 12, 2006.

At the first ever USA Rock Paper Scissors League Championship, "Drill" McGill defeated "Fast Twitch" Twitchel to win the tournament.

Programming Competitions

In Rock Paper Scissors programming competitions,[18] competitors will play hundreds of rounds in order to give them an opportunity to detect patterns in their opponents, less than optimal play which can be exploited.

References

  1. ^ http://www.nytimes.com/2005/04/29/arts/design/29scis.html?ex=1272427200&en=0fe7e3a883877ba2&ei=5088&partner=rssnyt&emc=rss
  2. ^ http://www.umop.com/rps25.htm
  3. ^ http://www.umop.com/rps7.htm
  4. ^ http://www.umop.com/rps9.htm
  5. ^ http://www.umop.com/rps11.htm
  6. ^ http://www.umop.com/rps15.htm
  7. ^ Presnell, Gregory (June 7, 2006). "Order of the court: Avista Management vs. Wausau Underwriters Insurance Co". CNN.com. Retrieved 2006-06-08.{{cite web}}: CS1 maint: year (link)
  8. ^ http://www.biology.ucsc.edu/faculty/sinervo.html
  9. ^ http://www.worldrps.com/index.php?option=com_content&task=view&id=14&Itemid=31
  10. ^ http://www.washingtontimes.com/national/20041210-120729-4008r.htm
  11. ^ http://www.npr.org/templates/story/story.php?storyId=1477870
  12. ^ http://www.cbsnews.com/stories/2003/10/29/earlyshow/contributors/melindamurphy/main580709.shtml
  13. ^ http://www.usatoday.com/news/offbeat/2003-10-27-rock-paper_x.htm
  14. ^ http://www.foxnews.com/story/0,2933,188380,00.html
  15. ^ http://www.voiceoftreason.net/hand-to-hand-combat.html
  16. ^ http://www.worldrps.com/index.php?option=com_gallery2&Itemid=30
  17. ^ http://www.usarps.com
  18. ^ http://www.cs.ualberta.ca/~darse/rsbpc2.html
  • Sogawa, Tsuneo (2000). "Janken". Monthly Sinica, Vol.11, No.5. (Japanese)
  • Culin, Stewart. (1895). Korean Games, With Notes on the Corresponding Games at China and Japan. (evidence of nonexistence of Rock, Paper, Scissors in the West)
  • Gomme, Alice Bertha. (1894, 1898). The traditional games of England, Scotland, and Ireland, 2 vols. (ditto)
  • Opie, Iona and Peter (1969). Children's Games in Street and Playground Oxford University Press, London. (Details some variants on Rock, Paper, Scissors such as 'Man, Earwig, Elephant' in Indonesia, and presents evidence for the existence of 'finger throwing games' in Egypt as early as 2000 B.C.)
  • Alonzo, S.H. and Sinervo, B. (2001). "Mate choice games, context-dependent good genes, and genetic cycles in the side-blotched lizard, Uta stansburiana". Behavioral Ecology Sociobiology Vol.49, pp.176-186
  • Sinervo, B., and Lively, C. (1996). "The Rock-Paper-Scissors Game and the evolution of alternative male strategies". Nature Vol.380, pp.240-243
  • Walker, Douglas & Graham (2004). "The Official Rock Paper Scissors Strategy Guide" Fireside (RPS strategy, tips and culture from the World Rock Paper Scissors Society).
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