Go (game)

Go

The Go board and pieces A traditional go board is wooden, with black painted lines. The stones are lenticular and fit closely together when placed on adjacent points.
Players	2
Setup time	No setup needed
Playing time	10 minutes to 3 hours, but some tournament games can last more than 16 hours to even 2 days
Chance	None
Age range	5+
Skills	Strategy, Observation

Go, also known as Weiqi in Chinese (simplified Chinese: 围棋; traditional Chinese: 圍棋), Igo in Japanese (Kanji: 囲碁), and Baduk in Korean (Hangul:바둑), is a strategic, zero sum, deterministic board game of perfect information originating in ancient China, before 2000 BC.

The objective of the game is to control a larger territory than one's opponent by placing one's stones so they cannot be surrounded and captured by the opponent, but can surround and capture any stones the opponent plays inside one's own territory. The game is now popular throughout the world, especially in East Asia, and on the Internet.

Overview

Gameplay

The game of Go is played by alternately placing stones on the vacant intersections of a 19×19 rectilinear grid. The two players, Black and White, try to maximize the territory they control by fencing off areas of the board with their stones, capturing any opposing stones that invade these areas, and protecting their own stones from capture.

The name "Go"

The English name Go originated from the Japanese pronunciation "go" of the Chinese characters 棋/碁; in Japanese the name is written 碁. The Chinese name Weiqi (圍棋,围棋) roughly translates as "encirclement chess", the "board game of surrounding", or the "enclosing game". Its ancient Chinese name is 弈 (Chinese: yì). The writings 棋/碁 are variants, as seen in the Chinese Kangxi dictionary. The game is most commonly known as 囲碁 (igo) in Japanese, because Japanese professionals taught the first Western players, who naturally used that name in early English language books and articles about the game. The Japan Go Association continued to play a leading role teaching Go to the West, publishing the English-language magazine Go Review in the 1960's, establishing Go Centers in the US and Europe and often sending professional teachers to Western nations for extended periods, so that many concepts for which there is no English equivalent have become known in the West by their Japanese names. The widespread use of Japanese terminology in the West notwithstanding, Chinese and Korean members of the international Go community, including professionals, continue to advocate for the primacy of their language in common usage. They point out that in recent years, many Chinese and Korean players have also taught Western students.

An alternative but uncommon spelling is Goe, proposed by Ing Chang-Ki, the late wealthy promoter of Go (particularly in Taiwan and the US), to differentiate it from the common English verb "go", but this spelling is not widely used, even in events sponsored by the Ing foundation.

History

Main article: History of Go

File:Go Kano Eitoku.jpg

In many East Asian cultures, Go was considered one of the most important skills a civilized person could learn. This screen was made by Kano Eitoku in the 16th century.

The origins of Go lie in China, with the earliest references from the 6th century BC (548 BC, source Zuo Zhuan). Except for changes in the board size and starting position, Go has essentially kept the same rules since that time, which makes it one of the oldest board games still played today.

According to legend, the game was first a teaching tool the ancient Chinese emperor Yao 堯 (2337 - 2258 BC) designed for his son, Danzhu, who he thought needed to learn discipline, concentration, and balance. Another suggested genesis for the game states that in ancient times, Chinese warlords and generals would use pieces of stone to map out attacking positions. Further and more plausible theories relate Go equipment to divination.

Before the industrial age in China, Go was long perceived as the popular game of the elite aristocratic class while Xiangqi (Chinese chess) was perceived as the game of the masses. Go was considered one of the cultivated arts of the Chinese scholar gentleman, along with calligraphy, painting and playing the Guqin, together known as 琴棋書畫 [3] (四艺, pinyin: Sìyì), or the Four Arts of the Chinese Scholar.

Go had reached Japan from China by the 7th century, and gained popularity at the imperial court in the 8th century. By the beginning of the 13th century, Go was played among the general public in Japan.

Guan Yu playing Go while having his wounds attended to

In 1603, Tokugawa Ieyasu created Japan's first unified national government. Almost immediately, he appointed the then best player in Japan, Honinbo Sansa, head of a newly founded Go academy (the Honinbo school, the first of several competing schools founded about the same time). These officially recognized and subsidized go schools greatly developed the level of play, and introduced the martial arts style system of ranking players. Players from the four houses competed in the annual Castle Games for status and the position of Godokoro, or minister of Go. Players like Honinbo Shusaku became national celebrities. The government discontinued its support for the Go academies in 1868 as a result of the fall of the Tokugawa shogunate.

In honour of the Honinbo school, whose players consistently dominated the other schools during their history, one of the most prestigious Japanese Go championships is called the "Honinbo" tournament.

Historically, Go has seen unequal gender participation. However, the opening of new, open tournaments and the rise of strong female players, most notably Rui Naiwei, has in recent years legitimised the strength and competitiveness of emerging female players.

Around 2000, in Japan, the manga (Japanese comic) and anime series Hikaru no Go popularized Go among the youth and started a Go boom in Japan. In January 2004, the Hikaru no Go manga began running in the US (monthly) edition of Shonen Jump.

Scott A. Boorman's The Protracted Game: A Wei-Chi Interpretation of Maoist Revolutionary Strategy , likens the game to historical events, saying that the Maoists were better at surrounding territory. Mao Zedong himself was an avid Go player.

Nature of the game

Although the game rules are very simple, the strategy is extremely complex. Go is the deepest game in the world. It is a perfect information, deterministic, strategy game, putting it in the same class as chess, checkers (draughts), and reversi (othello). Though superficially similar to draughts and reversi, go greatly exceeds them in depth and complexity, and transcends even the complexity of chess. Its large board and lack of restrictions allows great scope in strategy. Decisions in one part of the board may be influenced by an apparently unrelated situation in a distant part of the board. Plays made early in the game can shape the nature of conflict a hundred moves later.

The game emphasizes the importance of balance on multiple levels, and has internal tensions. To secure an area of the board, it is good to play moves close together; but to cover the largest area one needs to spread out. To ensure one does not fall behind, expansionist play is required; but playing too broadly leaves weaknesses that can be exploited. Playing too low (close to the edge) secures insufficient territory and influence; yet playing too high (far from the edge) allows the opponent to invade. Many people find the game attractive for its reflection of the contradictory demands of real life.

The game complexity of Go is such that even an introduction to strategy can fill a book, and many good introductory books are available. Go strategy and tactics gives a very brief introduction to the main concepts of Go strategy.

It is commonly said that no go game has ever been played twice, and this may well be true: on a 19×19 board, there are about 3³⁶¹×0.012 = 2.1×10¹⁷⁰ possible positions, most of which are the end result of about (120!)² = 4.5×10³⁹⁷ different (no-capture) games, for a total of about 9.3×10⁵⁶⁷ games. Allowing captures gives as many as

$10^{7.49\times 10^{48}}$

possible games, all of which last for over 4.1×10⁴⁸ moves. If that number were written down, with each digit as wide as a hydrogen atom, it would encircle the visible universe a trillion times. (For two comparisons: the number of legal positions in chess is estimated to be between 10⁴³ and 10⁵⁰, and physicists estimate that there are not more than 10⁹⁰ protons in the entire visible universe.)

Traditional Japanese equipment

After move 40 of round 1 of the 1989 Meijin tournament, little territory has been claimed.

Main article: Go equipment

Although one could play Go with a piece of cardboard for a board and a bag of plastic tokens, the finest equipment costs thousands of dollars. Many players derive great aesthetic and sensual satisfaction from playing with good equipment.

The traditional Go board (goban in Japanese) is solid wood, from 10–18 cm thick, and often stands on its own attached legs. It is preferably made from the rare golden-tinged Kaya tree (Torreya nucifera), with the very best made from Kaya trees up to 700 years old. More recently, the California Torreya (Torreya californica) has been prized for its light color and pale rings. Other woods often used to make quality table boards include Hiba (Thujopsis dolabrata), Katsura (Cercidiphyllum japonicum), and Kauri (Agathis). It is important to note that so-called "Shin Kaya" is a merchant's term which, while it may not deceive Asian buyers, does confuse Americans; the term shin means "new" (as in shinbun, "newspaper"), so "shin kaya" is best translated "faux kaya" - and indeed the woods so described are biologically unrelated to Kaya.

Players sit on rice-straw mats (tatami) on the floor to play. The pleasantly smooth stones (go-ishi) are kept in matching solid wood bowls (go-ke) and are made of clamshell (white) and slate (black). The classic slate is nachiguro stone mined in Wakayama prefecture and the clamshell from the Hamaguri clam. The natural resources of Japan have been unable to keep up with the enormous demand for the native clams and slow-growing Kaya trees; both must be of sufficient age to grow to the desired size, and they are now extremely rare at the age and quality required, raising the price of such equipment tremendously.

In clubs and at tournaments, where large numbers of sets must be maintained (and usually purchased) by one organization, expensive traditional sets are not usually used. For these situations, table boards (of the same design as floor boards, but only about 2–5 cm thick and without legs) are used, and the stones are made of glass rather than slate and shell. Bowls are often plastic if wooden bowls are not available. Plastic stones could be used, but are considered inferior to glass as they are generally too light, and stick to the fingers even after being released. Most players find that the lower price does not justify this distraction.

Traditionally, the board's grid is 1.5 shaku long by 1.4 shaku wide (455 mm by 424 mm) with space beyond to allow stones to be played on the edges and corners of the grid. This often surprises newcomers: it is not a perfect square, but is longer than it is wide, in the proportion 15:14. Two reasons are frequently given for this. One is that when the players sit at the board, the angle at which they view the board gives a foreshortening of the grid; the board is slightly longer between the players to compensate for this. Another suggested reason is that the Japanese aesthetic finds structures with geometric symmetry to be in bad taste.

Traditional stones are made so that black stones are slightly larger in diameter than white; this is probably to compensate for the optical illusion created by contrasting colours that would make equal-sized white stones appear larger on the board than black stones. The difference is slight, and since its effect is to make the stones appear the same size on the board, it can be surprising to discover they are not.

The bowls for the stones are of a simple shape, like a flattened sphere with a level underside. The lid is loose-fitting and is upturned before play to receive stones captured during the game. The bowls are usually made of turned wood, although small lidded baskets of woven bamboo or reeds make an attractive cheaper alternative.

The traditional way to place a Go stone is to first take a stone from the bowl, gripping it between the index and middle fingers, and then place it directly on the desired intersection. It is permissible to strike the board firmly to create a sharp click. Many consider the acoustic properties of the board to be quite important. The traditional goban will usually have its underside carved with a pyramid called a heso recessed into the board. Tradition holds that this is to give a better resonance to the stone's click, but the more conventional explanation is to allow the board to expand and contract without splitting the wood. A board is seen as more attractive when it is marked with slight dents from decades (or centuries) of stones striking the surface.

Rules

Main article: Rules of Go

This picture shows one black unit and two white units. Their respective liberties are shown with dots. Note that liberties are shared among all the stones of a unit. If White plays where his two units share a liberty, they will be connected into one.

Basic rules

If white plays at A, the black unit loses its last liberty, and is captured and removed from the board.

• Two players, Black and White, take turns placing a stone (game piece) on a vacant point (intersection) of a 19 by 19 board (grid). Black moves first. Other board sizes such as 13x13 and 9x9 may be used for teaching or quick games, but 19x19 is the standard size. Once played, a stone may not be moved to a different point.
• A vacant point adjacent to a stone is a liberty for that stone.
• Adjacent stones of the same color form a unit that shares its liberties in common, cannot subsequently be subdivided, and in effect becomes a single larger stone.
• Units may be expanded by playing additional stones of the same color on their liberties, or amalgamated by playing a stone on a mutual liberty of two or more units of the same color.
• A unit must have at least one liberty to remain on the board. When a unit is surrounded by opposing stones so that it has no liberties, it is captured and removed from the board.
• If a stone is played where it has no liberties, but it occupies the last liberty of one or more opposing units, then such units are captured first, leaving the newly played stone at least one liberty.
• "Ko rule": A stone cannot be played on a particular point if doing so would recreate the board position that existed after the same player's previous turn.
• A player may pass instead of placing a stone, indicating that he sees no way to increase his territory or reduce his opponent's territory. When both players pass consecutively, the game ends and is then scored.

A player's score is the number of empty points enclosed only by his stones plus the number of points occupied by his stones. The player with the higher score wins. (Note that there are other rulesets that count the score differently, yet almost always produce the same result.) For a more detailed treatment, see Rules of Go.

This is the essence of the game of Go. The risk of capture means that stones must work together to control territory, which makes the gameplay very complex and interesting. (Also see strategy.)

Go allows one to play not only even games (games between players of roughly equal strength) but also handicap games (games between players of unequal strength); see optional rules. Without a handicap, even a slight difference in strength will generally be decisive.

Game 5 of the 2002 LG Cup final between Choe Myeong-hun (white) and Lee Sedol (black) at the end of the opening stage; white has developed a great deal of potential territory, while black has emphasized central influence.

Optional rules

Optional Go rules may set the following:

• compensation points, almost always for the second player, see komi;
• compensation stones placed on the board before alternate play, allowing players of different strengths to play competitively (see Go handicap for more information);
• "superko": the ko rule (a move must not recreate the previous position) is extended to disallow any previous position. This prevents complex repetitive situations ("triple ko", "eternal life", etc.) from cycling indefinitely. [4]

Strategy

Main article: Go strategy and tactics

Basic strategic aspects include the following:

• Connection: Keeping one's own stones connected means that fewer groups need defense.
• Cut: Keeping opposing stones disconnected means that the opponent needs to defend more groups.
• Life: This is the ability of stones to permanently avoid capture. The simplest way is for the group to surround two "eyes" (separate empty areas), so that filling one eye will not kill the group and is therefore suicidal.
• Death: The absence of life, resulting in the eventual removal of a group.
• Invasion: Setting up a new position inside an area where the opponent has influence, as a means of balancing territory.
• Reduction: Placing a stone far enough into the opponent's area of influence to reduce the amount of territory he/she will eventually get, but not so far in that it is cut off from friendly stones.

The strategy involved can become very abstract and complex. Some high-level players spend years perfecting strategy. Go is often generally considered to be the ultimate strategy game, superior in depth of complexity to Chess, Xiangqi, and Shogi.

Philosophy

Go is deep, as playing against any stronger player will demonstrate (depth of the game as established by ELO ranking in Go). With each new level (rank) comes a deeper appreciation for the subtlety involved, and for the insight of stronger players. Beginners often start by randomly placing stones on the board, as if it were a game of chance — and they inevitably lose to experienced players. But soon an understanding of how stones connect for greater power develops, and shortly afterward a few basic common opening sequences may be understood. Learning the ways of life and death helps to develop one's situational judgement.

Further experience yields an understanding of the board, the importance of the edges, then the efficiency of developing in the corners first, then sides, then centre. Soon, the advanced beginner understands that territory and influence are somewhat interchangeable — but there needs to be a balance. It is best to develop more or less at the same pace as the opponent in both territory and influence. This intricate struggle of power and control makes the game highly dynamic.

Often, a comparison of Go and chess is used as a parallel to western versus eastern strategic thinking. Go is focused on building from the ground up (nothing to something) with multiple, simultaneous battles leading to a point-based win. Chess is said to be individualistic, as the object is to kill one individual piece (the king). Go is quite the reverse: individuals are only significant as they join or help determine the fate of larger forces.

A similar comparison has been drawn among Go, chess and backgammon, perhaps the three oldest games that still enjoy worldwide popularity. Backgammon is a "man vs. fate" contest, with chance playing a strong role in determining the outcome. Chess, with rows of soldiers marching forward to capture each other, embodies the conflict of "man vs. man." Because the handicap system tells each Go player where he/she stands relative to other players, an honestly ranked player can expect to lose about half of his/her games; therefore, Go can be seen as embodying the quest for self-improvement — "man vs. self."

Computers and Go

Computer as Go player

Main article: Computer Go

Go poses a significant challenge to computers. While there may be only a handful of masters in the world who can beat the best computer chess software, there are millions of people who can beat the best computer Go software. The best computer Go software manages to reach only 8-10k, the level a human beginner can expect to reach by playing regularly for several months.

The reasons why computers are not good at playing Go are attributed to many qualities of the game, including:

• The large board (five times the size of a chess board) allows many combinations of legal moves.
• Whereas in most games (e.g. chess, checkers) the game becomes simpler over time as pieces disappear, in Go, a new piece appears every move, and the game becomes progressively more complex.
• Unlike other games, a material advantage in Go does not mean inevitable victory.
• Non-local nature of the Ko rule
• High degree of pattern recognition involved.

On the other hand, a chess-playing computer, Deep Blue, beat the world champion in 1997. For this reason, many in the field of artificial intelligence consider Go to be a much better measure of a computer's capacity for thought than chess.

Computer as Go assistant

Computers become useful when they are used as tools to facilitate Go learners & players in the following ways:

• Internet-based Go servers allow people all over the world to meet, discuss games, and play one another. Online Go playing is becoming more and more popular. There are many strong players regularly playing online, even professionals. See Additional Resources below for more information.
• Electronic databases provide a convenient, efficient way to study Joseki, Fuseki, life and death situations and other problems.
• Computers offer a more organized and clearer way for authors to present their ideas in a step-by-step manner. More variations can be included in an electronic file than in a book due to space limitations.
• Computers make it easy to review and study game records. When replaying a game from a written record, one must locate the number of each move and then either imagine the current position or replay it on an actual board. The computer simply places each stone in sequence, as if the game were actually being played live online. Comments and variations (other play alternatives) can be attached to the games and stored readily in one file.
• Teachers can review a player's game records and attach variations and comments for later review by the student. Many teachers use this method online, instructing students they may have never met.
• Game records can be stored in a database. One can then search the database for a particular opening strategy, or for games by a particular player.

Go variants

Main article: Go Variants

There are many variations on the basic game of Go. Many of the modern variants are purely for fun, but some were invented with a specific purpose in mind. For example Capture Go is used for introducing the game to beginners, whilst Pair Go aims at the promotion of the game amongst Women. There are also historical regional variations that have now fallen out of fashion, such as Sunjang Baduk or Tibetan Go.

Go in popular culture

Go played using humans wearing hats (black or white) in place of stones (black or white) on a grid laid out in the grass.

Go has been mentioned in many novels and short stories published in the Orient, and occasionally turns up in Western media as well.

In 1951, Nobel Prize-winning author Yasunari Kawabata published The Master of Go, a short novel based upon an epic game that took place over the course of several months in 1938. An English translation appeared in 1972, around the time of Kawabata's death.

Go features (as "Wéi-chí") as a major theme in the Chung Kuo novels by David Wingrove. In particular it is the favourite pastime of and philosophical inspiration for the archvillan Howard Devore, who is a master of the game.

Go is featured in the cold war thriller, Shibumi by Trevanian. The central character spends his adolescence studying the game under a master, and the major chapters of the book reflect Go strategies.

Shan Sa, a Chinese writer who lives in France, wrote The Girl Who Played Go, where a Chinese girl plays Go with a Japanese soldier during World War II.

Go is featured in Scarlett Thomas's book PopCo. Alice Butler, the main character, works for a giant toy company where games of Go are encouraged to spark creativity.

First Kyu, a story by Dr. Sung-Hwa Hong, is about a young man whose life is overtaken by the world of Go in Korea.

The world of the fantasy series The Wheel of Time has a similar game, called Stones, with a hexagonal base shape instead of square.

In the science fantasy book The Left Hand of Darkness by Ursula Le Guin, Go is played by the two protagonists when they are stuck in an ice tempest.

The book The Way of Go by Troy Anderson likens the game to a Rosetta Stone for understanding the underpinnings of strategy, especially for business.

In the webcomic Disassemblance, the two main characters are occasionally seen discussing various subjects over a game of Go.

The game of Go plays a part in the American TV miniseries Wild Palms, which references a piece of computer technology called a "Go chip." Go figures prominently in the introduction of La Femme Nikita to the mysterious character of Jurgen during an important character arc in the television series La Femme Nikita. The game also appeared in an episode of Star Trek: Enterprise entitled "The Cogenitor" in which it was revealed that Charles Tucker plays the game. In another Gene Roddenberry show, Andromeda, Dylan Hunt and Gaheris Rhade both play a futuristic version of the game, apparently on three boards at once. During episode 15 of season 3 of the television show 24, several scenes took place in an underground Chinese Go club uncharacteristically populated by beautiful women. The characters even called it a "Go club". A 1980s TV series called Chessgame starred Terence Stamp as a spy master who would spend long periods studying a Go board.

Hikaru no Go is a manga and anime series, in which a boy is taught to play Go by the spirit of an ancient Go player. At the end of each episode in the original anime, there is a short segment of approximately three minutes where a simple concept of Go is taught. Through the first few episodes, a new player can be taught the concepts of the game in a very simple and easy to understand format. This segment appears to be mainly geared towards children. Hikaru No Go was extremely popular during its original run, and was also highly regarded by critics. A direct result of its success was that Go's popularity (which had been in decline for years in Japan) skyrocketed, especially amongst the young, and its popularity also increased in China, Korea, and many other countries which has a translation of the manga. Today interest in the game remains relatively high, in large part thanks to this series.

In the manga and anime series "Naruto", Shikamaru is mentioned to be a master at Shogi and Go. Although seemingly unmotivated and lazy, his intellect is proved when playing his sensei in these games. He never loses. In fact, a habit Shikamaru developed when playing Shogi and Go, in which Shikamaru places his hands together in order to calm himself and focus his thoughts, is even carried into his battles.

One popular Chinese/Japanese movie is Mikan no taikyoku (1982) aka The Go Masters. The movie depicts the time period when the Japanese army invaded China. The story begins when a Japanese Army Captain forces a famous Chinese Go player to play at a Go match. Due to resentment of the invasion, the Chinese player cuts off the finger that is used to hold Go stones. The story ends at a post-war time, where both the Japanese Captain and the Chinese Go player meet and play a peaceful game.

Go was depicted in the films Heaven Knows, Mr. Allison, A Beautiful Mind, Pi, Restless, After the Sunset and Hero among many others. See the Internet Go Filmography for an extensive list.

In the book Distraction by Bruce Sterling, the character Oscar Valparaiso teaches Go to a genetic researcher both as game of corporate and political strategy, and as a networking tutorial. He explains that creating "eye" groups makes a group of stones a permanent feature of the Go board even if the group itself is inside enemy territory.

In the novel Blunt : Les Treize Derniers Jours by Jean-Jacques Pelletier, the title character Horace Blunt uses Go to meditate and to try to understand an on-going terrorist plot. Each chapter of the book begins with a short text on the rules and strategies of the game.

In the Xbox game Jade Empire, in Tien's Landing, two masters of the games two different paths (Open Palm and Closed Fist) play Go in their minds, without pieces or boards. This may be secondary influence filtered through wuxia novels, which often feature Weiqi matches between martial artists.

The Go world

Ranks

File:Go pros and amateurs.jpg

Three Japanese professional Go players observe some younger amateurs as they dissect a life and death problem in the corner of the board, at the US Go Congress in Houston, 2003.

Main article: Go ranks and ratings

In Go, ranks are employed to indicate playing strength. Strictly speaking, we should only say rank, but not rating or level or grade. The rank system is tabulated from the lowest to highest ranks:

Rank Type	Range	Stage
double-digit kyu (級,급) (gup in Korean)	10-30k	Introductory
single-digit kyu	1-9k	Elementary to Intermediate
amateur dan (段,단)	1-7d (where 8d is special title)	Advanced
professional dan (段,단)	1-9p (where 10p is special title)	Expert

Time Control

Like many other games, a game of Go may be timed using a game clock. Game clocks are often used in tournaments so that all players finish in a timely way and the next round can be paired on time. Players may also use game clocks for casual play, for instance if playing an opponent who is known to play slowly. There are five timing methods:

• Standard Byo-Yomi: After the main time is depleted, a player has a certain number of time periods (typically around thirty seconds). After each move, the number of time periods that the player took (possibly zero) is subtracted. For example, if a player has three thirty-second time periods and takes thirty or more (but less than sixty) seconds to make a move, he loses one time period. With 60-89 seconds, he loses two time periods, and so on. If, however, he takes less than thirty seconds, the timer simply resets without subtracting any periods. This is written as <maintime> + <number of byo-yomi time periods> of <byo-yomi time period>.
• Canadian Byo-Yomi: After using all of his/her main time, a player must make a certain number of moves within a certain period of time -- for example, twenty moves within five minutes. Typically, players stop the clock, and the player in overtime sets his/her clock for the desired interval, counts out the required number of stones and sets the remaining stones out of reach, so as not to become confused. (Some game clocks, notably the Ing clock, do not permit this option.) If twenty moves are made in time, the timer is reset to five minutes again. This is written as <main time> + <number of moves to be completed in each byo-yomi time period> in <byo-yomi time period>. (The Origins of Canadian Byo-Yomi)

Most tournaments use standard or Canadian overtime. On the Internet, most players prefer a very short basic time -- as little as one minute -- moving into overtime right away so that the game progresses more quickly. There are three other overtime rules, but they are seldom used.

• Sudden Death: Each player receives a specific amount of time for the entire game with no overtime provisions. This rule is extremely rare except in "lightning" tournaments.
• Progressive Byo-Yomi: A variation of Canadian byo-yomi, where in each successive overtime period the player must make more moves, use less time, or both. For instance, in one amateur tournament the main time of fifty minutes was followed by twenty moves in five minutes, then forty moves in five minutes, then sixty moves in five minutes (the last time period being repeated until the game ended). Thus, this tournament's timing was written 50+20/5+40/5+60/5 (it is common to leave minutes as numbers without units while seconds are usually written in the form 5s).
• Penalty Points: If a player uses up to one-sixth of the basic time allotment (in addition to using all basic time), he/she incurs a two point penalty. Three such penalties can be imposed. If the player uses more than 50% of additional time, he/she forfeits the game. For instance, if the basic time is one hour per player, a player who goes beyond sixty minutes incurs a two point penalty. At seventy-one minutes, an additional two-point penalty is imposed, and a final penalty kicks in at eighty-one minutes. At ninety minutes, the player forfeits the game. This system was invented as part of "Ing's SST Laws of Go" but is seldom applied, even when other provisions of Ing rules are used.

Japanese Timing with a single byo-yomi period is equivalent to Canadian byo-yomi with one stone to be played in each period.

Top players

Main article: Go players

Although the game was invented and developed in China, Japanese players dominated the international Go scene for most of the twentieth century. However, top players from China such as Chen Zude (since the 1980s) and South Korea (since the 1990s) have reached an even higher level. Nowadays, top players from these three countries are of comparable strength, although top Korean players seem to have an edge, dominating the major international titles, winning 23 tournaments in a row between 2000 and 2002. All three countries have a number of professional Go tournaments. The top Japanese tournaments have a prize purse comparable to that of professional golf tournaments in the United States though tournaments in China and Korea are less lavishly funded.

Players from other countries have traditionally been much weaker, except for some players who have taken up professional courses in one of the Asian countries. This is attributed to the fact that details of the game have been unknown outside of Asia for most of the game's history. A German scientist, Otto Korschelt, is credited with the first systematic description of the game in a Western language in 1880; it was not until the 1950s that Western players would take up the game as more than a passing interest. In 1978, Manfred Wimmer became the first Westerner to receive a professional player's certificate from an Asian professional Go association. It was not until 2000 that a Westerner, Michael Redmond, achieved the top rank awarded by an Asian Go association, 9th dan.

See also

• Games played with Go equipment
• Go concepts
• Go handicap
• Go proverb
• Go competitions
• Iemoto
• List of board games
• List of Go servers
• List of Go software
• List of free Go programs
• List of Go topics
• List of Go organizations
• Nihon Ki-in
• Hanguk Kiwon
• Zhongguo Qiyuan
• Kansai Ki-in
• Computer Go
• Game complexity

Books

• The American Go Association maintains a complete list of the hundreds of books now available in English.
• David Carlton also maintains an extensive list with detailed reviews of every listed book.
• Learn to Play Go Volume I was written in an easy-to-read style by an American professional player. There are four more volumes in the series.
• Go for Beginners, Iwamoto Kaoru, Ishi Press, Tokyo, 1972. ISBN 0-87040-166-1
• Teach Yourself Go packs a lot of information into 240 pages.
• Go! More Than a Game and Go Basics use a game-analysis-based approach to explaining the game, and focus extensively on cultural and historical aspects.

The Book of Go by certified International Go Instructor William Cobb begins with "The Capture Game", a teaching method widely used in Japan, and builds toward an understanding of "real" Go.

• Go: A Complete Introduction to the Game by top Japanese pro Cho Chikun, alternates between technical instruction and chapters focusing on other aspects of the game.
• Lessons in the Fundamentals of Go, Kageyama Toshiro, Kiseido Publishing Company, 1978. (A more advanced book, suitable for people with a certain amount of experience.)
• Basic Techniques of Go, Haruyama Isamu, Nagahara Yoshiaki, Ishi Press, Tokyo, 1969. (Again, a more advanced book.)
• The Way of Go, Troy Anderson, Free Press, 2004. ISBN 0-7432-5814-2

External links

Learning Go

• The Interactive Way To Go is an excellent resource to learn the basics; includes Java applets.
• British Go Association's introduction to Go
• French Go Association's introduction to Go
• The Rules of Go
• How To Play Go from IGS operator PandaNet
• How To Play Go
• Samarkand is owned by Janice Kim 3p and has a very good online introduction. Her Learn to Play Go series is also popular and easy to follow.
• Tel's Go Notes where to look when you understand the rules and wonder what to do next.
• goproblems.com has over 3000 problems for practice in a Java applet.
• GoBase has a collection of 750 problems used in Korea to help develop players of amateur dan strength.
• Teach Yourself Go explains the rules of Go and, through step-by-step illustrations, shows how to play the game. The book also covers the origins of the game and its history and culture.
• Tsumego a Go problems mailing list. Each week, 4 problems from 20 kyu to 5 dan level set up by a professionnal player.

Resources

• Sensei's Library is a wiki devoted entirely to the game of Go - it even has special markup for displaying Go diagrams.
• The Usenet newsgroup rec.games.go has its own FAQ document, the rec.games.go FAQ.
• GoDiscussions.com Forum a web forum for discussing Go. Includes a database of Go product reviews
• Annotated Go Bibliographies Offers reviews of Go books old and new alike.
• Go Base has a particular emphasis on the coverage of the world Go scene, with regularly updated news about all major professional and amateur tournaments. You can register and access a huge database of Go games directly on the site. It also hosts articles, studying material, and much more.
• Go Equipment Information including classifications of boards by grain and classic composition.
• The Go Link Explorer A large collection of information and resources about Go, organised by category.
• Go Rule Dialects gives an overview about the main Go rule variations.
• Go can be played on the Internet against opponents from around the world on numerous Go servers:

Recorded games

• The popular SGF file format is used to exchange Go lessons and recorded games.
• Fuseki.Info - Online professional Go games database (more than 35000 games). Contains game records, game lists, fuseki and joseki trees. More than 3000 games for free.
• go4go.net - Approximately 10,000 professional games can be reviewed for free and without registration.
• Several free reading and authoring programs are listed at Gobase's SGF editors list
• gobase.org also hosts a database of more than 30000 professional Go games in SGF format (free registration required, which takes 1-2 days to process)
• My Friday Night Files provides more than 2000 professional games, including almost all known games of Cho Chikun
• A smaller collection of professional games in SGF format is available without registration at Andries E. Brouwer's Go Games.
• Amateur games are reviewed at The Go Teaching Ladder.