Go is a board game for two players, noted for being rich in strategic complexity despite its simple rules. It is known in China as 围棋 (Wéiqí); in Japan as 碁 or 囲碁 (Go or Igo); and in Korea as 바둑 (Baduk). Go reached the West through Japan, which is why it is commonly known internationally by its Japanese name, and much of its technical vocabulary is Japanese, although it originated in China and plays a much larger role in Chinese culture than Japanese.
The game is played by two players who alternately place circular black and white pieces called "stones" on the vacant intersections of a grid of 19×19 lines. Once placed on the board, stones cannot be moved elsewhere, unless they are surrounded and captured by the opponent's stones. The object of the game is to control a larger area of the board than the opponent.
Placing stones close together helps them support each other and avoid capture. On the other hand, placing stones far apart creates influence across more of the board. Part of the strategic difficulty of the game stems from finding a balance between such conflicting interests. Players strive to serve both defensive and offensive purposes and choose between tactical urgency and strategic plans.
The origins of Go are Shrouded in Myth. The game was invented in ancient China more than 5,500 years ago, so Go is probably Older Than Dirt and is thus the oldest board game continuously played today. It was considered one of the four essential arts of the cultured aristocratic Chinese scholar caste in antiquity. The earliest written reference to the game is generally recognized as the historical annal Zuo Zhuan. Archaeological evidence indicates that the early game was played on a board with a 17×17 grid, but by the time that the game spread to Korea and Japan in about the 7th century, the 19x19 board had become standard. The game is most popular in East Asia, but spread to other parts of the world. A conservative estimate places the number of Go players worldwide at approximately 27 million.
If you want a cursory animated introduction, try watching Hikaru no Go, which may have inspired many to play Go. For much more information check either The Other Wiki or visit Sensei's Library, a wiki devoted to the game. There is also a website keeping track of most of the professional world of the game. The PasoGo is a console that's entirely dedicated to the game, though it sold poorly.
Essays have been written about the differences between Go and Chess. Broadly speaking Go has simpler rules and is easier to learn than Chess, but is far more open in its possibilities. We were able to create computers that have mastered Chess by the mid-90s, but until 2016 Go eluded them. Some theorize this is for more than simply the size of the board adding astronomically more possible games of Go. Yet you could probably teach a five year old to play Go in an hour. This came to an end in March 2016, when Korean 9-dannote Lee Sedol lost 4-1 against Google's AlphaGo project. Notably, this utilizes a fundamentally different approach to AI than Chess. Chess computers operate in essence by brute force - calculating all possible options and looking for the best ones (in practice, they can speed this up by ignoring obviously bad options), while AlphaGo uses an approach called "Deep Learning", in which it analyzes tens of millions of games played by humans as well as billions of games played against itself and looks for common factors that differentiate moves that lead to wins from moves that lead to losses.
Not to be confused with the 1999 film Go, the short-lived early '80s television game-show, the travel-themed family board-game published by Waddingtons, the programming language developed by Google, or the Let's Play series by Achievement Hunter.
Sometimes used as the game of choice for the trope Smart People Play Chess.
Go provides examples of a number of the tropes to which this wiki is dedicated:
- Artificial Stupidity: For years, the best Go-playing computer programs were roughly on a par with fairly strong amateurs. Really strong professional players were still well beyond their reach. One of the major factors is that the very large board compared to those of similarly competitive board games like chess means there's just way, way, way too much calculation needed to reliably decide the optimal next move before the heat death of the universe. However, after years of Go programs steadily getting stronger, in 2016 Google's AlphaGo program defeated Lee Sedol, a top 9 dan human player, 3:0, winning the 5 game match before it had even finished. Some months later, an improved version called AlphaGo Master won 60 games against top professionals and lost none.
- Attack Pattern Alpha: Joseki, defined patterns of play that are generally considered to give the best possible benefits for both players. Note that unlike chess openings, joseki affect only the local board, and as such deviating from them is sometimes needed depending on the overall board condition.
- The Chessmaster: Just as in chess itself, making your stones survive a fight requires thinking several turns ahead to set up the shape you need or, alternatively, finding key weaknesses in your opponent's formation and then figuring out how to exploit them or forcing the opponent into a dead shape.
- Complete Immortality: Formations of stones with two eyes, considered "alive" in game terminology. To remove the stones, the opponent needs to completely surround the formation and fill in all its liberties... but with two eyes, this simply can't be done (eyes can't be played in unless you fill in all of its other liberties, but when another liberty is also an eye, this is physically impossible), meaning the stones are there to stay.
- Crazy-Prepared: Serious players study and memorise many sequences of best play, known as joseki. Strong players can usually reel off entire games from memory.
- Flipping the Table: A traditional (if humorous) way to Ragequit is known as the "nuclear tesuji," where the losing player flings the board at the wall◊, uppercuts the winner and storms out. (Troper General's Warning: Don't actually try this, it has never been seen as good sportmanship.)
- Some books on Go depict on their covers paintings of samurai doing this.
- Four Is Death: Zigzagged.
- In the middle of the board, capturing a single stone requires filling in the liberties around it, entailing surrounding the stone with four others.
- When eyes with four spaces in the middle are involved, the eye is functionally alive if all four inner spaces are in a straight line since even if the opponent plays first to try and disrupt the shape, the owner can simply make two eyes and live; on the other hand, if they're T-shaped or in the form of a square... you have problems.
- Idiosyncratic Episode Naming: Some famous games have exotic titles like "The Ear-Reddening Game", and probably most famous of all, "The Blood-Vomiting Game" (See Serious Business below).
- Kyu and Dan Ranks: Go players are ranked according to their playing strength. Complete beginners are ranked at roughly 30-35 kyu (30-35k), and as they improve, their rating reduces, so a 10k player is stronger than a 15k player. This is because kyu ranks are based on the number of handicap stones players would need to win half their games against a First Dan player (See PVP Balanced below), and the stronger player needs a smaller handicap. After winning promotion to First Kyu (1k), the highest kyu rank, the next step is Shodan or First Dan (1d), and dan ranks rise with greater strength from First to Ninth Dan, the highest amateur rank. Professional players have their own ranking system, rising from First (1p) to Ninth (9p) Dan. Go may have been the first game or sport to use the kyu/dan system.
- Jigoro Kano, founder of Judo, was inspired by Go and its Dan and Kyu system to create his own Judo ranking system, and associated it with colored belts (and also brought it to swimming). The whole Judo ranking system then inspired various other arts such as Karate and Tae-Kwon-Do and made it a popular concept.
- Master-Apprentice Chain: The Four Houses of the Edo period were each a lineage of Go study, where the master would select and adopt a successor from among his pupils, who would in turn become head of the house and adopt his successor.
- Metagame: Thousands of pages of analysis have been written over the centuries. The only game with a comparable literature is Chess.
- Minimalism: Unlike many board games, which involve different kinds of spaces and pieces, Go only has one kind of piece per player and a plain grid to play on.
- Obvious Rule Patch: The ko rule, intended to break up positions where both players can repeatedly capture the same two stones. In a situation where it applies, the player that just had a stone captured cannot re-capture the opponent's stone for one turn, and must make a play elsewhere, giving the other player an opportunity to end the ko fight if they don't feel like responding to whatever move the first player made.
- Play-by-Post Games: Nowadays, internet Go servers and e-mail have largely replaced this.
- Pronoun Trouble: When writing about Go (in the abstract rather than when referring to specific players), it is customary to refer to one player as "he" and the other as "she". Unfortunately, some believe black should be male and white female, while others appeal to ancient Taoist tradition and argue for the opposite.
- PVP Balanced: Enormous attention is given to giving both players an even chance:
- Although each player has identical resources, black customarily plays first, which gives him an advantage. In a game between equally-strong players, white receives a scoring allowance called komi to compensate her for this. The exact size of komi is periodically adjusted based on exhaustive analysis of professional game statistics.
- In a game between players of different strength, the weaker player takes black, and komi may be reduced or eliminated. If the difference in strength is sufficient, black may also be allowed to place a number of "handicap stones" on the board before the game begins, to give him a head start. The idea is to allow both players to share an enjoyable game, so the size of the handicap is adjusted to their respective playing strengths. This leads to differences in playing strength being expressed in terms of "stones", as in: "Ben is four stones stronger than Bill". The handicap is traditionally calculated by comparing the players' Kyu and Dan Ranks (see above).
- Japanese rules require the handicap stones to be placed on specific points, the first nine of which are normally marked on the board as the hoshi (star) points. Japanese rules specify patterns for handicaps of up to seventeen stones, but various unofficial patterns have been published for handicaps of up to forty-one stones, the traditionally-accepted difference between a complete beginner and the strongest amateur player. Chinese rules allow free placement of handicap stones, so potentially there is no limit to the size of handicap that could be given.
- An alternative to very large handicaps is to play on a smaller board (13x13 and 9x9 being by far the most common sizes). Handicap stones have a much greater effect on a smaller board (a common rule of thumb is that one handicap stone on 13x13 is approximately equivalent to three in 19x19), so the game can be played evenly without the need for so many of them, making the play more sensible.
- Serious Business: Oh so very much:
- In ancient China, Go was one of the four arts a scholar was required to learn in order to be considered a member of the "gentlemen caste".
- Full-time professional players competing for multi-thousand dollar prizes.
- Well-attended after-school classes for school-children.
- Full-time students studying for examination tournaments to qualify to become professionals.
- Extensive television coverage of pro games, including dedicated channels!
- Pro games lasting up to sixteen hours over two days (they used to be much longer).
- Unwritten but deeply-rooted conventions of proper behaviour and play, over which there is much discussion.
- As the board was being cleared after the legendary four-day "Blood-Vomiting Game" of 1835, the defeated player Akaboshi Intetsu, collapsed, coughing up blood, and died ("within a few months" though).
- Strategy, Schmategy: One Go proverb states that "Learning joseki drops two stones strength, studying joseki gains four stones strength." In other words, a complete newbie will usually play better than someone who has learned the standard patterns of play, but hasn't yet learned how and why they're used in an actual game.
- Suicide Attack: Better known as the "throw-in", where you deliberately put a stone that can be taken immediately on an opponent's key point, ruining their formation and usually costing them far more.
- Tournament Play: Professional tournaments are regarded as the highest form of the game by many players, and success in them is essential to the careers of pro players. Amateur national rankings are also based on performance in tournaments.
- Why Mao Changed His Name: The Chinese name for the game is 围棋. This used to be romanised as wei-chi, but since the adoption of pinyin romanisation, it is written wéiqí. The correct pronunciation remains (roughly) "way-chee".