Rock, Paper, Scissors chart

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.

Contents

Game play[edit]

SssStein.jpg SssPapier.jpg SssSchere.jpg
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 "1...2...Break!", "1 ... 2 ... 3 ... Shoot!", "1 ... 2 ... 3!", "Once ... Twice ... Thrice ... Shoot!" "Rock ... Paper ... Scissors ... Shoot!", "Rock ... Paper ... Scissors!", "Scissors... Paper... Stone!", "Zim... Zam... Zee!", "Scissors... Paper... Rock!" or "Ro ... Sham ... Bo!" while simultaneously bouncing their fists. On "Shoot", "Go", or "Scissors", the players simultaneously change their fists into any of three "objects":

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

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

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

Japanese Gameplay[edit]

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

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[edit]

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.

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.)

In order to prevent the unconscious forming of patterns after many hours of competition, and to combat many psychological techniques used in competitive play, a professional player may often employ the use of gambits. A gambit is a predetermined series of throws. Gambits may also be used in an attempt conceal or minimize "tells". A serious combatant may practice a gambit thousands of times until the mind has only to name the series of throws and muscle memory takes care of the rest. Much as a great martial artist or dancer will practice the same techniques until their conscious "higher" minds are not needed, and rather it is the "lower" unconscious mind which takes control.

Mathematically there are 27 possible gambits. While local names may vary there are ten internationally recognized and labelled gambits.[1]

The Avalanche Rock Rock Rock
The Bureaucrat Paper Paper Paper
The Toolbox Scissors Scissors Scissors
The Crescendo Paper Scissors Rock
The Denouement Rock Scissors Paper
Fistful O' Dollars Rock Paper Paper
Paper Dolls Scissors Paper Paper
Scissors Sandwich Paper Scissors Paper
The Dynasty Rock Rock Scissors
The Bail-lift Rock Paper Rock

Gambit RPS Strategy[edit]

Building on the ideas of gambit play, a structured variant of the standard game can be played where both players choose a predetermined set of three throws each and play them against one another, without changing throws mid-game. Once the throws are exchanged, the player winning more throws out of three wins. Typically, 9 three-throw sets are played to determine a match winner. Should players tie, the set is considered drawn and the match would continue. The three-throw sets can also be called "runs".

This variant, called PRPS or Professional RPS[2], can offer more strategic ideas for both players, since the player winning the first throw of their three-throw set can gain significant advantage over the opponent for that set. When a player leads after the first throw, there will always be six winning outcomes (one +3 result, two +2 results and three +1 results), two drawing results and only one losing result. Taking the classic run "R-P-S", the player would win the first throw against any run by the opponent that started with Scissors. Here there would be one +3 result (versus S-R-P, where the R-P-S run defeats all the opposing throws), two +2 results (versus S-P-P & S-R-S), three +1 results (S-S-P, S-R-R, S-P-S), two drawing results (S-P-R & S-S-S) and only one losing result (versus S-S-R). This pattern holds true for all runs where one opponent takes the advantage after the initial throw, and gives that player around an 89% chance of either winning or drawing, but not losing, the set.

Players may develop further strategies by noticing which types of runs their opponents are known to play. The 27 three-throw runs can also be classified as Heavy, Mixed or Straight Runs, depending on the number of instances a throw is included in the run. A "Heavy" Run is one that utilizes two of any given throws in its run, such as R-R-P and S-P-S, each of which has two of the same throw and one non-matching throw. They are the most common run with 18 configurations. A "Mixed" Run is one that uses three different throws in the run without repeating any of them, such as R-P-S or P-R-S. They are the next largest catagory with 6 configurations. "Straight" Runs, also called "Exclusive", are the final catagory with only 3 configurations where the player simply chooses one throw and repeats it three times (R-R-R, P-P-P & S-S-S).

The different run types interact with each other in very specific ways, and knowing how they will interact can allow players to force definitive outcomes. A Mixed Run versus a Straight Run will always result in a draw. For example, R-P-S against either R-R-R, P-P-P or S-S-S are all drawn sets. However, a Mixed Run versus a Heavy Run wil always result in one player winning. To demonstrate this, pick a Mixed Run and have someone use any of the Heavy Runs against it. One player will win, but the players will never draw. Taking a Straight Run versus a Heavy Run will also never result in a drawn set, nor will taking any type of run against another of the same run (for example, mixed vs. mixed will always be definitive). Players may use this knowledge, coupled with the general strategy listed above, to gain an advantage over their opponents.

Cheating[edit]

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.

The opening ritual before the actual throws are made ("1… 2… 3… Shoot!" or “Rock, paper, scissors, shoot!”), called "priming", is intended to get both players in sync so as to ensure simultaneous delivery of throws. This can be used to an advantage when two players are meeting for the first time, since it is often unclear as to what the priming speed will be. The tendency is to default to the priming speed of the faster player. This allows the faster priming player the luxury of dictating the flow of play and causes their opponent to dedicate more energy to "catching the prime" rather than concentrating on delivering an effective throw.

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. This is often seen among live action role-players.

Among children and immature adults, the "bomb" (thrown the same as a rock, except with the thumb sticking straight up rather than hidden) is employed as a desperate attempt to thwart one's opponent. Needless to say, this maneuver is illegal, and those who employ this tactic are scorned for cheating. However, it could be assumed that scissors could beat bomb in the sense of cutting the fuse. Other variants of this include the finger, volcano, fire, gun, squirrel, and the flagon tri, the latter being an automatic win. However, in certain Live-action Role-playing games, the bomb is a legal move used in particular situations, such as the ultimate level of a skill.

Retribution can be accomplished after a failed throw by punching, slapping, or poking your opponent depending on the move in hand.

Variations[edit]

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 representing different objects. Minor variation is also observed in the standard game play.

Another variation is known as RPS-25[3] 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, 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,[4] RPS-9,[5] RPS-11,[6] and RPS-15.[7]

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.

Multiplayer RPS[edit]

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[edit]

Extreme RPS uses the same rules as regular RPS accept that the losing "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 in the upper arm.

Math and non-transitivity[edit]

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[edit]

Rock, Paper, Scissors was invented by the Japanese.[citation needed]

There is no record of Rock, Paper, Scissors in the West before there was direct contact with Asia.[citation needed] The Chinese and Koreans use Cloth along with Rock and Scissors, while the Japanese have adopted Paper.[8]

Pop culture trivia[edit]

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 or they may just be smart-alecs.

Federal case[edit]

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.[9]

Evolutionary strategy[edit]

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, hereditable mating strategy:[10]

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[edit]

WRPS Sanctioned Tournaments[edit]

Starting in 2002, the World Rock Paper Scissors Society (WRPS) standardized a set of rules for international play [11] 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.[12][13][14][15][16][17] WRPS events are noted for their large cash prizes, elaborate staging, and colourful competitors.[18] In 2004 the championships were broadcast on the U.S. television network Fox Sports Net.

World Championship results since 2002[edit]

Year Host City Medal Champion Gender Nationality
2002 Toronto Gold Pete 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[edit]

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[edit]

In April 2006, the inaugural USA Rock Paper Scissors League Championship was held in Las Vegas, Nevada.[19] 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.

Template:Spoiler

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

Programming Competitions[edit]

In Rock Paper Scissors programming competitions,[20] 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[edit]

  1. ^ http://www.worldrps.com/index.php?option=com_content&task=view&id=20&Itemid=33
  2. ^ http://www.chessandpoker.com/rps_rock_paper_scissors_strategy.html
  3. ^ http://www.umop.com/rps25.htm
  4. ^ http://www.umop.com/rps7.htm
  5. ^ http://www.umop.com/rps9.htm
  6. ^ http://www.umop.com/rps11.htm
  7. ^ http://www.umop.com/rps15.htm
  8. ^ Jan Ken Pon - Some Historical Data
  9. ^ Presnell, Gregory (June 7, 2006). "Order of the court: Avista Management vs. Wausau Underwriters Insurance Co.". CNN.com. Retrieved 2006-06-08. 
  10. ^ http://www.biology.ucsc.edu/faculty/sinervo.html
  11. ^ http://www.worldrps.com/index.php?option=com_content&task=view&id=14&Itemid=31
  12. ^ http://www.washingtontimes.com/national/20041210-120729-4008r.htm
  13. ^ http://www.npr.org/templates/story/story.php?storyId=1477870
  14. ^ http://www.cbsnews.com/stories/2003/10/29/earlyshow/contributors/melindamurphy/main580709.shtml
  15. ^ http://www.usatoday.com/news/offbeat/2003-10-27-rock-paper_x.htm
  16. ^ http://www.foxnews.com/story/0,2933,188380,00.html
  17. ^ http://www.voiceoftreason.net/hand-to-hand-combat.html
  18. ^ http://www.worldrps.com/index.php?option=com_gallery2&Itemid=30
  19. ^ http://www.usarps.com
  20. ^ http://www.cs.ualberta.ca/~darse/rsbpc2.html

External links[edit]