National variants
The difficulty in defining the rules of Go has led to the creation of many subtly different rulesets. They vary in areas like scoring method, ko, suicide, handicap placement, and how neutral points are dealt with at the end. These differences are usually small enough to maintain the character and strategy of the game, and are typically not considered variants. Different rulesets are explained inTibetan Go
Tibetan Go is played on a 17×17 board, and starts with six stones (called Bo) from each color placed on the third line as shown. White makes the first move. There is a unique ko rule: a stone may not be played at an intersection where the opponent has just removed a stone. This ko rule is so different from other major rulesets that it alone significantly changes the character of the game. For instance, snapbacks must be delayed by at least one move, allowing an opponent the chance to create life. Finally, a player who occupies or surrounds all four corner points (the 1-1 points) receives a bonus of 40 points, plus another 10 if the player also controls the center point.Sunjang baduk
Sunjang baduk is a different form of Go (baduk) that evolved in Korea, which dates to the 16th century. Its most distinctive feature is the prescribed opening. The starting position dictates the placement of 16 stones (8 black, 8 white) as shown, and the first move is prescribed for Black at the center of the board. At the end of the game, stones inside friendly territory, which are irrelevant to boundary definition, are removed before counting territory. It became obscure in the 1950s when it was largely replaced by modern go due to Japanese influence. There are around 45 surviving game records of Sunjang baduk, mostly from the 1880s. The oldest known game record was published in the ''Bangneki
In another Korean variant, bangneki, the players wager on the outcome of the game. A fixed stake ("''bang''") is paid for every ten points on the board by which the loser is beaten.Batoo
Batoo is a modern Korean variant. The name stems from a combination of the Korean words ''baduk'' and ''juntoo'' (“battle”). It is played entirely in cyberspace, and differs from standard Go in a number of ways, most noticeably in the way in which certain areas of the board are worth different points values. The other principal difference is that both players place three stones before the game begins, and may also place a special “hidden stone”, which affects the board as a regular stone but is invisible to the opponent. Batoo became a short-lived fad among young people in Korea around 2011.Variants altering the rules of play
No Contact Go
In No Contact Go, stones may not contact enemy stones. After consecutive passes, players score their number of stones plus the number of empty points adjacent to only their stones. An even simpler variant removes the option of passing, and makes the player that has no legal move lose the game.First Capture
The first player to capture a stone wins. It was invented by Japanese professional Yasutoshi Yasuda, who describes it in his book ''Go As Communication''. Yasuda was inspired by the need for a medium to address the problem of bullying in Japan, but soon found that "First Capture" also works as an activity for senior citizens and even developmentally delayed individuals. He sees it as a game in its own right, not just as a prelude to Go, but also as a way to introduce simple concepts that lead to Go. For the latter purpose, he recommends progressing to "Most Capture", in which the player capturing the most stones wins. This variation is often called Atari Go in the West, where it is becoming increasingly popular as a preliminary means of introducing Go itself to beginners, since, afterward, it is natural to introduce the idea of capturing territory, not just the opponent's stones.Miai-Go
In Miai-Go, each player plays two moves at once, and their opponent decides which of the two should stay on the board.Stoical Go
In Stoical Go, invented by abstract game designer Luis Bolaños Mures, standard ko rules don't apply. Instead, it's illegal to make a capture if your opponent made a capture on the previous move. All other rules are the same as in Go. Suicide of one or more stones is not allowed, and area scoring is used. All known forced Go cycles are impossible with this rule. The nature of the rule itself suggests that forced cycles are either impossible or astronomically rarer than they are in Go when the superko rule is not used. Ko fights proceed in a similar manner to those of Go, with the difference that captures and moves answered by captures aren't valid ko threats. Although snapbacks are not possible in the basic variant (as it is necessary to make a ko threat before any consecutive capture occurs), they can be explicitly allowed with an extra rule while retaining the property that all known forced cycles are impossible.Environmental Go
Environmental Go, also called Coupon Go, invented byTime Is Money Go
Each player begins the game with a decided upon amount of time (no byoyomi). At the end of the game, when the score is counted, the number of seconds remaining on each player's clock is added to their respective score.Cards Go
In Cards Go players draw from a pack of cards contain instructions to play one of a fixed set of commonly occurring shapes. If the said shape cannot be placed on the board, then an illegal move is deemed to have been played, which necessitates resignation.Multi-player Go
In Multi-player Go, stones of different colors are used so that three or more players can play together. The rules must be somewhat altered to create balance in power, as those who play first (especially the first four, on a four-cornered board) have significant advantage. There are various optional rules that enable cooperation between the players, e.g. division of captured stones among neighbors, or forming alliances for adding up territory points. A variant called parallel multiplayer go also exists, where the moves are announced simultaneously. If two moves overlap, they count as passes.Paper and Pencil Go
Paper and Pencil Go is a Go variant that can be played with just paper and pencil. Unlike standard Go, games played under these rules are guaranteed to end in a finite number of moves, and no ko rule is needed. Nothing is ever rubbed out. It differs from standard Go in the following ways: * Surrounded stones are not captured, but just marked. Points occupied by marked stones count as territory for the surrounding player, but neither player can play on them for the remainder of the game. This implies that any group which touches a marked stone is unconditionally alive. * Suicide is allowed, i.e., you can make a play such that one or more of your own stones become marked. * Area scoring is used. (Conventional Go can also be played on paper by drawing circles of different colors. Captured stones are marked with a line. Then if the square is replayed, a smaller circle is placed inside the larger circle.)Omino Go
Also named Tetromino Go. Devised by R. Wayne Schmittberger, each player is allowed to play up to four stones in a turn, provided they are solidly connected on adjacent points. (There are five four-stone patterns possible, two three-stone patterns, and one two-stone pattern, ignoring rotations and reflections.) There is no komi; Black is restricted on his first turn to playing no more than two stones. The winner is determined by Chinese scoring: occupied and surrounded points each count 1 point; captured stones do not have point value. The inventor suggests a 15×15 square-celled board using square-tiled pieces.NoGo
The first player forced to capture one or more stones or to make a suicide move loses. Players try forcing their opponent into a losing move by building territory only they can play on.KillAll Go
In this variant, black is given a large handicap, and must prevent white from forming a living group.Quantum Go
Quantum Go is a Go variant which provides a straightforward illustration of interesting quantum phenomena. Players alternatively play pairs of go stones which are entangled, in the sense that each entangled pair of stones will reduce to a single go stone at some point in the game. A process of quantum-like collapse occurs when a stone is played in contact with one of the stones in an entangled pair.Block Go
Block Go was a variant of Go played at the 20th AnnualTwo Stone Go
All standard rules apply, but after the Black (the first player) places one stone on the very first move both players place two stones each subsequent turn (similar to the game ofBorderless Go
In this variant, intersections at the opposite sides of the board are considered adjacent, like on aSygo
Sygo is a two player abstract strategy game invented in 2010 byCoin Go
In Coin Go, a stone cannot be played on certain intersections of the board by either player. A coin may be placed on these intersections as a visual aid. Stones adjacent to a coin do not have a liberty at the coin. There are different ways to determine intersections occupied by coins: * Intersections are chosen (randomly or not) at the beginning of the game before either player takes a turn. A possible alternative is players take turns placing coins on the board. * An even number of coins is split between both players. The game begins with no coins on the board. Players may use a turn to place a coin on the board. A possible alternative is to allow spending a coin to remove a coin from the board. * (The two methods above may also be combined) Coins may not be captured through liberty shortage. For scoring, coins do not contribute to territory. Normal scoring rules apply. Since playing as Black might have the potential of being a significant advantage in this variant, players may use the "Pie rule" to determine who plays which color: # Player A plays Black's first move. # Player B decides whether to be Black or White for the remainder of the game.Variants for more than two players, but not altering the mechanism of the game
Pair Go
Outline
Rules
The official rules of Pair Go, as determined by the Japan Pair Go Association, are given below. The rules are available in five languages: Japanese, English, Chinese, Korean, and Spanish.The Rules of Pair Go (Japan Pair Go Association, revised 2002) Also, the rules were decided in 1991,The First 25 Years of Pair Go (Japan Pair Go Association 2014) the year after the game's invention, and their drafting was supervised by Yoshikuni Ichiro, Honorary President of the Japan Pair Go Association, who also served as director of the Cabinet Legislation Bureau. A male player and a female player form a pair; the members of the pair sit on the same side of the Go board. Players of the same gender face each other over the board. The male and female players play alternately. The first move is made by the female member of the pair taking black; next, the female member of the pair taking white plays; next, the male member of the pair with black plays; next, the male member of the pair with white plays. This rotation continues throughout the game. The members of a pair must not consult each other or give advice. Conversation is permitted only for deciding to resign or to check whose turn it is to play. In consulting the partner about resigning, the player whose turn it is asks their partner, who must reply only yes or no. When a mistake is made in the order of players, an objection can be made only about the move just played. When a rotation error has been made, a move cannot be replayed. A penalty of three points is levied on the pair that made the mistake. If it is confirmed that partners have made an illegal exchange of information, the pair concerned forfeits the game. When passes are made in succession, the game concludes. When handicap games are played in tournaments for amateurs, the ranks of the two players in a pair are added, then divided by two to calculate the “pair points.” The handicap is decided by the difference from the pair points of the other pair.Invention
Pair Go is a new mind sport born in Japan that was invented in 1990 by Hisao Taki, who was the president of NKB inc. as a means of increasing female and children participation in the game.The First 30 Years of Pair Go (Japan Pair Go Association 2019) It was popularised by the Japan Pair Go Association by hosting tournaments including the International Amateur Pair Go Championship started in 1990. They hoped that this increase in itself would add a new appeal to the game.Tournaments
IAPGC first introduced Pair Go to Europe in 1992 at European Congress in Canterbury, England. The first European Pair Go Championship (EPGC) was held in Amsterdam in 1995. Since 1997 it has been a regular event, hosted by a different country each year. So far it has been in France, Netherlands, Czechia, Bosnia, Poland, Romania, UK, Germany and Russia. Typically teams from about 15 countries take part. Since 2004 they have been competing for points, as well as prizes, to allow their country to qualify for the IAPGC. There is also a popular Pair Go event at the annual European Go Congress. Amateur Pair Go tournaments have been held in the United States at the U.S. Go Congresses since 2005 at least and in Denver, Colorado. In the US, more than eighty players participate in the North American Pair Go Championship at the US Go Congress every year. With the support of the World Pair Go Association, the AGA is expanding the presence of Pair Go in the US with a series of sponsored regional tournaments, culminating in an internet playoff for free tickets to the US Go Congress for the North American Pair Go Championship. The tournament that determines the world's number one amateur pair each year is the International Amateur Pair Go Championship, which was founded in 1990. A Japanese Pair Go tournament in which top male and female professionals from the Nihon Ki-in and the Kansai Ki-in compete, the Professional Pair Go Championship, was founded in 1994. In 2008, Pair Go became an official sport at the Mind Sports tournament. In 2010, it was included in the Guangzhou Asian Games; in 2011, it was an official sport at the SportAccord World Mind Games, which is recognized by the IOC. The following international professional tournaments have been held: the Pair Go World Cup 2010 in Huangzhou, China; the Pair Go World Cup 2016 Tokyo; the Pair Go World Championship was held each year from 2017 to 2019. In 2019, an international tournament was held to commemorate the 30th anniversary of the birth of Pair Go. At present, the game is played in 75 countries and territories (as of September 2020). The Pair Go World Cup 2022 Japan, in which the world's top professional and amateur players competed, took place from March 17 to March 21, 2022, in Tokyo. Ratings determined by the rating system on the Internet Go salon Pandanet will be used as the unified basis for the rankings of all the players taking part. The handicaps will be decided by the “pair points” calculated on the basis of the rankings determined by this rating system. Ratings in Go differ in different parts of the world, meaning that there are often big differences in strength among players of the same nominal ranks, so the lack of a unified rating system has been a problem. Since the games in the Official Pair Go Handicap Tournament will use ratings determined by a unified system, so it will be possible to eliminate these differences and calculate the correct handicaps. For this reason, it is expected that this tournament will have an epoch-making effect on the popularization of Pair Go.Olympics
The international popularization of Pair Go has made big strides. In 2008, the World Pair Go Association (WPGA) was founded with the aim of further popularizing and developing Pair Go. As of September 2020, the association had 75 countries and territories affiliated with it. Matsuura Koichiro, the 8th Director General of UNESCO, serves as president. Also, the committee to Make Pair Go an Olympic Sport was launched on June 30, 2015. In October 2019, the Japan Go Federation, an incorporated foundation, was founded by the Japan Pair Go Association in cooperation with the Nihon Ki-in and the Kansai Ki-in; it is the only body that represents the Japanese Go world internationally. It also is carrying out activity to secure the adoption of Go and Pair Go as Olympic sports in the future.Rengo
Rengo (), which is the origin ofVariants requiring memory of the position
Blind Go
One (as a handicap) or both of the players cannot see the board in this variant. Therefore, they have to remember the whole position. This is considered much more difficult than playingOne Color Go
The two players use stones of the same color. This variation is regarded as a useful tool for developing one's memory and reading skills by forcing both players to remember who placed each stone. An external program or a third person may be used to keep track of who captures what in case one or both players forget the true color of a stone.Variants with limited knowledge of the position
These variants are not purely strategic games, as the element of luck is quite important.Shadow Go
This game requires two players, a referee and three playing sets. Each player sees only his own board, while the referee can see them both and also has his own set. This variant is usually played on a 9×9 board. Players place stones on their boards, with no knowledge of what other players are doing. A referee keeps track of the game on the central board. If any player makes an illegal move, the referee informs him about it (some play that the referee says only that the move is illegal, while some, that the player is told whether the intersection is occupied or there is illegal ko capture). The player is allowed to make another move.Rengo Kriegspiel
This is a crossover between rengo and shadow Go. There are two teams with two players each, a referee and five Go sets. The players move alternatingly as in rengo. Each player keeps track of their own moves on their own board; they are not informed about teammates' or opponents' moves. The referee keeps track of the complete game and informs a player if their move was illegal, in which case they can try again. The referee removes captured stones from all affected boards.Non-standard boards
Although Go is most commonly played on a board with 19×19 lines, 9×9 and 13×13 boards are also available. They are used by beginners and by players who want a game that finishes more quickly. Due to flexibility of configuration, the two smaller sizes are more often played on the online Go servers such asOther than 2D
Alak is a Go-like game restricted to a single spatialSee also
* Abstract strategy game for other board games sometimes compared to Go *References
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