Go is a game that is played on a square grid of lines, typically 19 intersections to a side. 13x13 and 9x9 are also common.

For beginners, smaller boards are recommended.

There are two players, each using a set of black and white stones respectively.

Objective

Win by surrounding the most territory by the end of the game.

Rules

There are 4 main rules to this game.

1) Game Flow

  • Black begins in standard matches
  • Each player takes a turn to place a single stone on any of the intersections.
  • Stoned placed on the board stay on that intersection UNLESS they are captured by the opponent.

2) Capturing of Stones

  • The empty intersections immediately adjacent to a stone are called liberties. Liberties are NOT the diagonal intersections, only the adjacent ones
    • A stone in the middle of the board has 4 liberties
    • A stone in the side of the board has 3 liberties
    • A stone in the corner of the board has only 2 liberties
  • Stones that have all of their liberties occupied by stone of the opposite color are considered captured and taken by the opponent.
  • Adjacent-connected stones of the same color share their liberties, and if captured, are captured as a group.
  • A group that is under threat of being captured (having only one liberty) are said to be in atari
  • You are not allowed to play stones in intersections where it would be immediately captured by the opponent.

3) Ko - Eternity

  • You may not immediately replicate a previous board position.
    • Unlike chess which allows for players to repeat moves and thereby force a draw, Go does not allow draws by repetition due to the Ko Rule
  • However, after 2 turns of placing stones elsewhere on the board, a previous position can be repeated. This often leads to “Ko Fights”

4) Concluding the game

  • If a player feels like they have no more worthwhile moves to play, they can pass.
  • If both players pass in succession, the game ends.
  • Dead stones are immediately removed from the game as “captured”
  • Territory is then counted for each player as the number of intersections surrounded by their stones
  • A point counts as a territory when it can only reach stones of a single player’s color.
  • The scores are then reduced by the number of one’s stones captured by the opponent. This is frequently done by placing those captured stoned in one’s territories.
  • In games against evenly matched opponents, the white player is given an advantage in points as compensation for going second. This is usually 6.5 or 7.5 points, with a half point for breaking ties. This is called Komi
    • For more uneven matchups, white is given a smaller komi
    • Sometimes black will get to start with multiple stones on the board

On Life and Death

  • As an implication of Rule 1 and Rule 2, a group is considered alive if they can make 2 eyes.

Ko Fights

  • Good evaluation of ko fights is difficult because of how difficult it can be to evaluation points on the board.

Position Evaluation

  • Positional evaluation is critical in the game of Go

Resources