The Objective
Weiqi is a game about surrounding, whether you're enclosing empty areas to claim territory or aiming to capture your opponent's stones. Any empty space that you fully surround with an alive group becomes your territory Players take turns placing stones on the intersections of the board. Once placed, stones do not move. They can however be captured if they lose all their liberties.
Capturing
A single stone has up to four liberties, the empty points directly next to it. When stones of the same color touch along these points, they form a group. A group shares all its liberties. Your opponent reduces a stone's liberties by playing on those adjacent empty points. The edge of the board also limits liberties. When a stone or group has no liberties left, it is captured and removed from the board.
Suicide Rule
You cannot place a stone where it would have zero liberties unless doing so captures opposing stones and gains liberties that way.
Ko Rule
Ko prevents infinite loops. You cannot immediately recapture a stone in the exact same board position and you must play somewhere else first. Many players use a strategy with Ko Threats to win a Ko.
Eyes
Two separate internal empty points within a group. A group with two eyes is unconditionally alive because the opponent cannot fill both eyes without violating the suicide rule.
Handicap
When a higher ranking meets a lower rank, they may play a handicap game with commonly 2 to 5 help stones. These are placed at the Hoshi.
Komi
Because Black plays first, they gain a natural advantage. To balance this in even games, White receives a fixed number of bonus points called komi. Japanese rules has the standard of 6.5 Komi points. The half point prevents ties.
Ending the Game
The game ends when both players pass consecutively. A player passes when there are no beneficial moves left. The players then remove all dead stones (those within the opponent's territory) without secure two eyes. The dead stones are placed inside their own color's territory reducing the points there. In the Japanese ruleset, only empty intersections count as points, so unnecessary moves can lose points.
