Go is an adversarial game with the objective of surrounding a larger total area of the board with one's stones than the opponent. As the game progresses, the players position stones on the board to map out formations and potential territories. Contests between opposing formations are often extremely complex and may result in the expansion, reduction, or wholesale capture and loss of formation stones.
A basic principle of Go is that a group of stones must have at least one "liberty" to remain on the board. A "liberty" is an open "point" (intersection) bordering the group. An enclosed liberty (or liberties) is called an "eye", and a group of stones with two or more eyes is said to be unconditionally "alive".Such groups cannot be captured, even if surrounded.A group with one eye or no eyes is "dead" and cannot resist eventual capture.
The general strategy is to expand one's territory, attack the opponent's weak groups (groups that can be killed), and always stay mindful of the "life status" of one's own groups.The liberties of groups are countable. Situations where mutually opposing groups must capture each other or die are called capturing races, or semeai. In a capturing race, the group with more liberties (and/or better "shape") will ultimately be able to capture the opponent's stones. Capturing races and the elements of life or death are the primary challenges of Go.
A player may pass on determining that the game offers no further opportunities for profitable play. The game ends when both players pass,and is then scored. For each player, the number of captured stones komi is subtracted from the number of controlled (surrounded) points in "liberties" or "eyes", and the player with the greater score wins the game.
Games may also be won by resignation of the opponent.