The game of eastern origin, known as Weiqi in China, Igo in Japan, and Baduk in Korea, probably originated in China some 4,000 years ago; it later spread to Korea and Japan. In the West, where it is called Go, it was not practiced until the late 19th century. It is now growing in popularity worldwide.
It is played on an initially empty 19×19 line board, although smaller boards, 13×13 or even 9×9, are standard for beginners. The two players involved have many black or white stones, respectively, which are placed on the board.
The game’s main objective is to use your stones to form territory by surrounding empty areas of the board; capturing is not the ultimate goal but serves to gain that territory. The winner is the player with the most points, which corresponds to controlling more territory.
Initially, the board is empty. The player starts with black stones, and then the turn alternates from one player to the other.
There is also the possibility of playing with a handicap: the stronger player gives an advantage to his opponent of 2 to 9 stones; in these cases, the weaker player plays with black rocks, the advantage stones are initially placed on certain predetermined intersections and it is the player who plays with white stones who freely takes the first turn.
Each move consists of placing a new stone on an unoccupied area of the playing field but not of moving stones that have already been placed on the field.
To understand the dynamics and purpose of the game, several concepts need to be defined:
A group of stones is considered captured when it has no freedom, i.e., when surrounded by the opponent’s player’s stones, with the charged group of stones having no free space within itself.
In the following picture, you can see that 6 white stones are in a capturing situation:
In particular, an isolated stone is captured if it is surrounded by 4 opponents’ stones; if the stone is on the side or in the corner of the board, it is sufficient if it is surrounded by 3 or 2 opponents’ stones respectively.
The captured stones are removed from the board.
Two reasons can hinder the installation of a stone:
The illustration shows the position where the junction where the white stone cannot be placed is visible:
The game ends with an agreement between both players. When either player believes that it is impossible to make more territory, capture more opponent’s stones or reduce the opponent’s territory, he must pass rather than placing a stone on the board.
Endgame protocol begins when both players consecutively pass.
At the end of the game, players decide which stones will inevitably be captured if the game continues. These stones are called dead stones and are fished out before points are counted.
If the players disagree on which stones are alive and dead, the game starts again.
While the basic rules are standard, there are some aspects of go whose laws vary from place to place and do not affect the general dynamics of the game or its strategy. The most notable part is the method of scoring; there are two ways:
This is the most commonly used system, with the advantage that it forces players to avoid placing more stones than necessary at the end of the game to avoid a penalty to their score. When playing online, its disadvantage is that one player can cause a disagreement when deciding which stones are dead, forcing the opponent to make extra moves and thereby gain an advantage in the score.
As usual, in many games, the starting player has a particular advantage. To compensate for this advantage, the score is usually adjusted by awarding a certain number of points to the opponent, called komi.
This advantage is usually adjusted depending on the rules used, the size of the board, and the results of statistical analysis of games played by experienced players. It is usually a decimal value to avoid draws and is usually around 6.