Science Fair Project Encyclopedia
Rock, Paper, Scissors
Rock, Paper, Scissors (sometimes with the elements in its name permuted and/or Rock replaced with Stone and/or Paper with Cloth, but also known as Roshambo, Rochambeau, Row-Sham-Bow, Ick-Ack-Ock, Janken, Mora, Morra Cinese, Gawi-Bawi-Bo, JanKenPon, Ca-Chi-Pun or Farkle) is a popular hand game most often played by children. It is often used 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, including ultimate frisbee and university debating, 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 a quick Rochambeau. It is also often used as a method for creating appropriately biased random results in live action role-playing games, as it requires no equipment.
Like Go and Mahjong, Rock, Paper, Scissors was also invented by Chinese. According to a book named Wǔzázǔ (五雜俎 or 五雜組) written by Xiè Zhàozhì (謝肇淛) in the late Ming period, warlords of Later Han played a game called shǒushìlìng (手勢令), which is considered to be Rock, Paper, Scissors.
There is no record of Rock, Paper, Scissors in the West before they had direct contacts with Asians. Western writers in the late 19th century only mentioned it as an Asian game. Chinese and Koreans use Cloth along with Rock and Scissors, while Japanese have somehow renamed it Paper. These facts suggest Americans imported Rock, Paper, Scissors from Japan in the 19th century.
|Each of the three basic hand-signs (from left to right: rock, paper and scissors) beats one of the other two.|
Two players each make a fist. They count together "1 ... 2 ... 3 ... Go!", "Rock ... Paper ... Scissors ... Shoot!", "Rock ... Paper ... Scissors!", or "Ro ... Sham ... Bo!" while simultaneously bouncing their fists. On "Shoot", "Go", or "Scissors", each player simultaneously changes their fist into one of three hands (or weapons):
- Rock (or Stone): a clenched fist.
- Paper (or Cloth): all fingers extended, palm facing downwards, upwards, or sideways (thumb pointing to the sky).
- 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:
- Rock blunts Scissors (rock wins)
- Scissors cuts Paper (scissors win)
- Paper covers Rock (paper wins)
If players choose the same weapon, the game is a tie and is played again.
Often times, the short game is repeated many times so that the person who wins two out of three or three out of five times wins the entire game.
Australians often play the game as "scissors, paper, rock!" or "paper, scissors, rock!", with emphasis placed on the word "rock", or as "hammer, scissors, paper!", with similar emphasis. The throw is made on the final word (either rock or paper) so that players only have two calls to synchronize the play.
Due to the influence of the Japanese-Brazilians, Brazilians prime the game as "jan ... ken ... po!", with emphasis placed on the "po". The throw is made as "po" is called, so that as with the Australian variation, only two calls are made before the play.
Strategy between human players obviously involves using psychology to attempt to predict or influence opponent behavior. It is considered acceptable to use deceptive speech ("I'm going to play a rock") to influence your 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. 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 Roshambo 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 of the first tricks learned by a Roshambo novice is to hold back a throw of paper until the last possible moment to dupe an opponent into believing that you may actually be throwing a rock. This allows you the extra few milliseconds for fine-tuning your approach and delivery. Both paper and scissors also have this ability; however, unless you are employing a "double-back" strategy, cloaking a paper throw is likely to draw an instinctive paper from your opponent.
The opening ritual before the actual throws are made ("1 ... 2 ... 3 ... Go!"), 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.
There are multiple variations on Rock, Paper, Scissors of varying popularity and humor content. These fall into two main types: cosmetic and functional variations. Related hand games are treated in a separate section.
Cosmetic variations are changes to the game that do not alter the core concept of the game in any fashion, but only how it looks to observers. Within this category would be the names of symbols and specific gestures used to indicate each of the three symbols, as well as resulting consequences of the game's outcome.
Names of symbols
When changing the names of the symbols, typically each symbol has its own gesture associated with it. These may be simple hand gestures as in traditional Rock, Paper, Scissors, or whole-body gestures.
- Chinese and Koreans call the three standard symbols Cloth, Scissors, and Rock, in this order. This is the original.
- Japanese call them Gū, Choki, and Pā, which are onomatopoeic words for Rock, Scissors, and Paper respectively. The game itself is called Janken. There are several less common varieties with different hand signs, such as Mushi-ken ("vermin hands"), in which Snake beats Frog, Frog beats Slug, and Slug beats Snake. Kitsune-ken ("fox hands") uses gestures rather than hand signs, in which Fox beats Village Headman, Village Headman beats Gun, and Gun beats Fox. Tora-ken ("tiger hands") is another gesture version; Watōnai (Koxinga) beats Tiger, Tiger beats Mother (Tagawa Matsu), and Mother beats Watōnai.
- In Singapore, Dragon, Water, Stone is played. Dragon beats Water, Water beats Stone, and Stone beats Dragon.
- In Myanmar, Commander beats Soldier, Soldier beats Tiger, and Tiger beats Commander. The idea being that while the Commander has authority over the Soldier, he is too old and physically unfit to take on the Tiger. However, the Soldier being young, strong and well trained, beats the tiger. The game's gestures are not limited to the palm as most of the other rock, scissors and paper variations. The Commander's gesture is done with arms placed on hips. The Tiger's gesture is done with riased arms and spread claws, like a tiger about to pounce. The Soldier's gesture is done with the thumbs and index fingers of both hands in the "pistol" position.
- In India, Elephant beats Human, Human beats Ant, and Ant beats Elephant.
- In The Netherlands RPS is also know als Steen, Dynamiet, Schaar (Rock, Dynamite, Scissors), because blowing up the rock is easier to imagine than packing the rock.
- One of the most popular modern varieties is called Cat, Microwave, Tinfoil. Cat beats Tinfoil by ripping it up, Tinfoil beats Microwave by starting a fire, and Microwave beats Cat by cooking it. This version was created because, to the creators of Cat, Microwave, Tinfoil, it doesn't make sense that Paper beats Rock by covering it. As it doesn't damage Rock, while on the other hand it can destroy Paper by tearing it. However, Cat, Microwave, Tinfoil doesn't make much sense either, since it has been proved that tinfoil in a microwave does not damage the microwave oven (but does often produce arcing and possibly fire), contradicting common misconception.
- Bulldog, Mongoose, Cobra is another variation, with Bulldog beating Mongoose, Mongoose beating Cobra, and Cobra beating Bulldog. This is the only known variation where sound effects are ritualized and crucial - if you fail to make the Cobra's hissing sound, for example, it is powerless against the Bulldog.
- In Gorilla Man , Gorilla Man beats Ninja or Karate Man, Karate Man beats Gun Man, and Gun Man beats Gorilla Man. The entire body is used, and the making of sound effects is proper form. This variant is especially played at Camp Agawam.
- In Ninja, Cowboy, Lion, Ninja beats Cowboy, Cowboy beats Lion, and Lion beats Ninja. This variation is also sometimes played with a Bear instead of a Lion or a Hunter instead of a Cowboy.
- In Cockroach, Foot, Nuclear Bomb , Foot stomps on and squashes Cockroach, Nuclear Bomb blows up Foot, and Cockroach survives Nuclear Bomb. This variation was formed by Steven Hyde on That '70s Show, as Fez refused to play Rock, Paper, Scissors with him anymore.
- In another scheme, Hero beats Bear, Bear beats Maiden, and Maiden beats Hero. This version is typically played with the entire body; the specific stances vary, but common examples are given. One version is called Bear, Housewife, Cowboy. Players begin by standing facing away from each other approximately 1 meter apart, as if preparing for a duel. They count to three, and on "Go", each player jumps 180 degrees into one of three poses. The Bear pose has legs apart and arms up with hands formed into claws with an optional roar sound effect. Bear eats Housewife. The Housewife pose has legs together and arms close to the body in a gesture of surrender with an optional eek sound effect. Housewife marries Cowboy. The Cowboy pose has legs apart with both hands at the hips in the traditional gun signals of thumbs straight up, index fingers pointing forward and other fingers curled, with optional bang sound effect. Cowboy shoots Bear.
While traditional Rock, Paper, Scissors (called "Gawi-Bawi-Bo" and pronounced "Kai-Bai-Bo") is popular among Koreans, a popular related game is Muk-Chi-Ba. A unique variant of Muk-Chi-Ba that adds a layer of complexity was reported in New York City, reportedly created by a Korean-American student at Columbia University.
What makes this version unusual is that firstly, the hand symbols are different (involving poses with both arms); and secondly, the game does not end when one player beats another, but rather when a player with the advantage gets the other player to follow this disadvantaged pose with another in which both players are displaying the same one of the three symbols.
This game is enjoyed for its sudden reversals and the quick thinking it requires.
In South Africa, the game is referred as Ching-Chong-Cha (phonetic).
Another variation is strip Rock, Paper, Scissors called Yakyū-ken, a Japanese party game, where every time a player loses, he or she has to remove an article of clothing. This goes on until one of the players is completely naked.
Originating in Kansai, Osaka janken follows the chant "Osaka janken, maketara kachi yo" (Osaka janken, the loser is the winner).
Extreme Rock, Paper, Scissors
Another variation is Extreme Rock, Paper, Scissors, in which the winner of each game may use their winning hand position to assault the loser. Paper becomes a slap, rock a punch and scissors a poke (usually in the sternum). This adds the extra challenge of trying to get the more painful positions without the opponent realizing it, while offering a chance to legitimately hit them.
Functional variations actually change game play, including associated strategies. These include the number of players and number of symbols (either as additional symbols in the circle, or a more complex topology).
Number of players
The game is easily adaptable to more than just two players. This variant works remarkably well, even for large groups. The rules are the same, with the following exceptions:
- If all three weapon types are played, or only one type of weapon is played, the round is considered to be a draw. A new round begins.
- If there are only two different weapon types showing between all of the players, then all of the players showing the losing weapon are eliminated.
Odd or Even (2 symbols)
In Odd or Even, one player selects odd or even. The only choice in weapons are "one" (a fist with outstretched thumb) or "two" (a fist with outstretched thumb and forefinger). The values signified by the players are added, with the first player winning on a correct prediction about the result. With a choice between two values (it does not matter that they are 1 and 2, only that they are not both odd or even) the game is balanced, and there is no benefit from making the call. Should the player allow three (or any odd number) values to choose from, either odd or even would be a more probable outcome with both players acting randomly. (That is because n choices make n2 possible outcomes. Squares of even numbers are even, squares of odd numbers odd.)
See also Odd or Even.
Cantonese have been playing God, Chicken, Gun, Fox, Termite, which is an asymmetrical game unlike Rock, Paper, Scissors. God beats Chicken and Gun; Chicken beats Termite; Gun beats Chicken and Fox; Fox beats Chicken; and Termite beats God. God and Fox draw; Gun and Termite draw; and Fox and Termite draw.
Malaysians also have an asymmetrical five-hand variation, Bird, Rock, Gun, Board, Water. Bird beats Water; Rock beats Bird and Board; Gun beats Bird, Rock, and Board; Board beats Bird and Water; and Water beats Rock and Gun.
There exists a modern five-hand variation called Rock, Paper, Scissors, Spock, Lizard, which is carefully crafted so that each weapon defeats exactly two other weapons, and is defeated by exactly two other weapons. Specifically, rock defeats scissors and lizard, paper defeats rock and Spock, scissors defeat paper and lizard, Spock defeats scissors and rock, and lizard defeats Spock and paper. (The rationale is that Spock smashes scissors and vaporizes rock, but is disproved by paper, while the lizard is crushed by rock and decapitated by scissors, but eats paper and poisons Spock.) The game can be similarly altered for 7, 9, 11, etc. As long as there are an odd number of weapons, a balanced game can be created, with each weapon beating half the weapons and losing to half the weapons. The advantage of playing with more weapons is that ties become increasingly unlikely. The disadvantage is that an increasingly complex resolution table must be memorized (as well as any accompanying gestures).
The game of Monkey Kombat from Escape From Monkey Island is effectively a five-object variation, with stances (known as Anxious Ape, Bobbing Baboon, Charging Chimp, Drunken Monkey and Gimpy Gibbon) replacing the objects. The trickiest part of this exercise is the learning of the transitions between the stances (achieved by permutations of the four sacred monkey words Ack, Oop, Eek and Chee).
Players often add other "weapons" to the game on an ad-hoc basis, but it is very likely that this will result in an unbalanced game. In particular, four (or any even number) of weapons cannot be made balanced, unless some pairs of weapons result in a draw; there will always be some weapons that will be superior to others. It also loses some of the aesthetic simplicity of the game, which is otherwise one of the simplest possible games of skill.
Dynamite is an example of a trump play. It is expressed as the extended index finger or thumb, defeats only rock, but is defeated by either scissors or paper. Therefore, anything dynamite will beat, paper will beat; and anything dynamite will tie, paper will tie or beat. Given that paper performs better by tying against another paper, it is always better to use paper than to use dynamite, and dynamite is useless. In game theory, it is said that paper has weak dominance over dynamite.
Fire and water are also potential "trumps", and have been used in ultimate frisbee tournaments. Fire will beat any of the standard weapons (rock, paper, scissors), but because of the power its play is restricted to a single use in the player's entire lifetime. Thus, the subject of when to "throw fire" is quite controversial. Water, which is referred to as "piss" in some circles, may be played as many times as one wishes, but will lose to anything except fire. Fire is typically played by gently waving all fingers; water is played by forming a circle with the thumb and index finger.
Another possible addition is that of well to the original three. Well beats both rock and scissors, because when a rock or a pair of scissors are thrown down a well, they'll fall, but loses to paper because when a paper sheet is thrown, it is likely that it will simply float to the side of the well. The use of this new weapon makes for an extremely unbalanced game, since it doubles the chances of winning while retaining the same amount of chances of losing. In principle, this variation makes Rock useless (as Well beats Scissors and loses to Paper just like Rock does, yet Well beats Rock) and replaces it, leaving the players with the same game and different symbols.
Yet another variation includes string, which wraps around both Rock and Paper, but is cut by Scissors. As Well renders Rock useless, this variation renders Paper useless, as String defeats it and interacts with Rock and Scissors the same.
In some sub-groups of ultimate frisbee, the use of "Inversion" is allowed as an additional strategic element. In this variation, at the last moment before the actual throw, any player involved may call out "Inverted". If invoked, this effectively reverses the relationship of each of the throws involved (ie. rock beats paper beats scissors beats rock). In situations where multiple players simultaneously call out "Inverted", the inversion is applied in an odd/even way whereby an odd number of Invert calls equals an inverted throw (ex. scissors beats rock), while an even number of Invert calls equals a negation of inversion and the throw results are interpreted as originally intended (ex. rock beats scissors).
As an added level of sophistication, the additional throw of "Kring" may be introduced in games involving inversions. The Kring hand symbol is a claw-like gesture with the bent fingers curled downward. The Kring will beat everything. It can also be thrown any number of times. While at first this throw would seem to be unbalancing, the addition of the inversion call will subsequently turn the Kring into a "loses to everything" throw. Traditionally, the person throwing the Kring will physically invert their hand a number of times equal to the number of inverts called upon the throw. A upside-down Kring (claw-like hand palm upward) is an all around loser.
There are Roshambo tournaments held occasionally. Some of the Roshambo websites spoof comparable sites for other games. Real Roshambo tournaments are an interesting psychological exercise. Obviously, the strategy dictated by game theory is to pick each choice one-third of the time randomly. However, a human cannot be truly random, and the skill in the tournament involves inciting and exploiting nonrandom throws from one's opponents. The ability for certain experienced players to consistently reach the finals of high level tournaments is a strong testament to skill influencing the outcome of the game.
In Japan, Janken tournaments are often held on television variety programs, especially between popular actors, and the game is also often used by advertising kiosks as tool for audience participation.
WRPS International World Championships
Starting in 2002 the World Rock Paper Scissors Society (WRPS) standardized a set of rules for international play and has overseen an annual International World Championships (as well as many regional and national events throughout the year). These championships have been widely attended by players from around the world and have attracted widespread international media attention. WRPS events are noted for their large cash prizes, elaborate staging, and colourful competitors. Since 2005 the championships have also been broadcast on the US television network Fox Sports Net.
WRPS International World Championship Results (Modern Era)
|2002||Toronto, Ontario||Pete Lovering||Male||Canadian|
|2003||Toronto, Ontario||Rob Kruger||Male||Canadian|
|2004||Toronto, Ontario||Lee Rammage||Male||Canadian|
Rock, Paper, Scissors in Pop Culture
- In the Sega Master System game Alex Kidd in Miracle World, Alex Kidd plays JanKenPon with his enemies. Also, the main villain in the game is called Janken .
- A cosmetic variation was presented on That '70s Show: Foot, Cockroach, Nuclear Bomb. Foot beats cockroach by smashing it, nuclear bomb beats foot by blowing it up, cockroach beats nuclear bomb by surviving the blast.
- Piers Anthony presents another cosmetic variation of this game as a plot device in his fantasy series Xanth called Fire, Water, Sand. There are two different schools of thought on how the elements interact. Mermaids believe that Water quenches Fire, Fire melts Sand, and Sand covers water. Dragons believe that Fire evaporates Water, Water dilutes Sand, and Sand puts out Fire. This misunderstanding is the cause of a long-standing feud between the two clans.
- In the TV series South Park, Cartman and his friends play the game "I'll Rochambeau you for it", by kicking the opponent in the crotch. The first one to fall over loses the game. This of course means the first person to go is usually the winner. This is a way of choosing, and it's called Rochambeau, yet it is important to note that game play is obviously unrelated to the actual game of Rock, Paper, Scissors as described here.
Other games related to Rock, Paper, Scissors
- Pointing version: In this variant the winner of each round of the game must make a pointing gesture - up, down, left, or right - with the aim of making their opponent look in that direction. If the loser of the initial rock-paper-scissors can avoid looking in that direction they steal the victory. However if they even glance in the pointed direction, they are confirmed as losers.
- During the 1980s, an action figure line called Battle Beasts was released by Hasbro in both America and Japan. Each sci-fi themed figure had, in the middle of its chest, a random symbol revealed through warming it via body heat through a finger. Players would randomly select a figure and challenge each other to "battle." The three symbols (wood, water, and fire) had a Rock, Paper, Scissors relationship (wood beats water, water puts out fire, fire burns wood). Later, the "sunburst" symbol, which could beat all other symbols, was introduced. The toy line was vaguely connected to the Transformers series.
- In many real-time strategy computer games, there are three types of troops, with each troop type beating one and losing to another. For example, archers beat pikemen, cavalry beat archers and pikemen beat cavalry or, in a modern setting, light armored vehicles beat infantry, tanks beat light armored vehicles and infantry beat tanks. There are also some turn-based strategy games with a similar dominance structure; however, sometimes the troops are replaced with weapons regarding what dominates what.
- In Magic: The Gathering, the deckbuilding strategies tend to break down into a few major types. Though only an approximation, usually paper-rock-scissors is compared to aggro-control-combo. Since there is a random element, a matchup is not usually a 100% chance of victory for the dominant deck. The optimal strategy can be found using probability, and depends on what you expect other players to do.
- Pokémon is sometimes compared to a very complex variant of paper-rock-scissors, particularly the trio of starting Pokémon available in all the games, except Pokémon Yellow. Although the overall type chart is likely unbalanced (which in practice doesn't usually matter too much), the three starting Pokémon's types are very balanced, with Grass (dries up Water), Fire (burns Grass), and Water (douses Fire). However, there are similar trios of Pokémon that do not have balanced type relations – Eevee's three stone-evolved forms, Vaporeon, Jolteon and Flareon; the three legendary birds, Articuno, Zapdos and Moltres; and the legendary trio from the Gold, Silver and Crystal versions, which are Suicune, Raikou and Entei. In each case, the Electric-type Pokémon (Jolteon, Zapdos and Raikou) is superior. Note, however, that just as with Magic: The Gathering, a type advantage does not provide a 100% chance of beating your opponent, only an increased chance.
- Many role-playing games also have an elemental system (usually involved with the magic system) which, while usually less complex, also provides superiority to certain types when used against other types.
- Eon Games' Darkover board game used a rock-paper-scissors style combat system. The two players would each hide a "power disk", which could be a sword, a keeper, or a starstone. The power disks are revealed simultaneously; sword beats keeper, which beats starstone, which beats sword. Two swords or two keepers would tie, but ties between starstones were resolved through "psychic combat".
- In Uru Live, the short-lived online component of the computer game Uru: Ages Beyond Myst, explorers could play a D'ni game called "Ahyoheek", which is a sophisticated Rock, Paper, Scissors implementation. This has been re-enabled in Untěl Uru, the new fan-run online service. It is played on a special pentagonal table with electronic scorekeeping and holographic display built in.
- Taasen is a chess-like game with a complex capturing move based on Rock Paper Scissors. It is featured in Unicorn Jelly.
- Trimok is a fast chess-like game based on rock paper scissors. A freeware version is available and actual game boards and pieces have been made (see external links).
- The Super Famicom puzzle game Ougijanken, similar to Dr. Mario, is branded as a Ranma game, but is essentially based on Rock, Paper, Scissors.
- In the Looney Labs board game Cosmic Coasters, the two players decide the outcome of battles between spaceships by playing Rock, Paper, Scissors.
- In Zork Grand Inquisitor, the player, as Lucy Flathead plays a game of Strip Grue-Fire-Water against Antharia Jack , essentially the same as Rock, Paper Scissors, except the game kept score by the number of items of clothing players removed. (No nudity was ever shown).
Math and non-transitivity
Rochambeau 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 Rochambeau: 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, Rochambeau could be called "antitransitive" because if A strictly defeats B, and B strictly defeats C, A necessarily loses against C.
- 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. (an 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)
- Rock Paper Scissors Spock Lizard
- Regional variations on Rock Paper Scissors
- World Rock Paper Scissors Society
- Page with some history
- Rock Paper Scissors aka RoShamBo on a webcam
- Trimok, Chess-like game based on Rock Paper Scissors
- Taasen, Chess-like game featured in Unicorn Jelly
- RoShamBo Programming Competition
- Atlantic Monthly Article February, 1860 Article Roba Di Roma (Add a link to the Project Gutenberg file when it gets finished) (Hm.. Here's the relevant link to the MARCH 1860 issue, which contains the string "Roba Di Roma", but I don't see anything in it about rock paper scissors... Am I missing something?)
- BombBeatsThemAll, an AIM Rock Paper Scissors bot that allows two people to play RPS over AIM
- Stanford University's RoshamBot
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