Go is a two-player strategic board game that originated in China more than 4000 years ago.

• Objective
• Board
• Liberties and Territory
• Play
• Capture
• Suicide moves
• Ko
• Komi and Handicap
• End of Game

The objective of Go is to have a higher score than your opponent after both players have passed a turn. Your score is the addition of the intersections that your stones are surrounding plus the number of your opponent's stones you have captured.

The board is a grid of 19 horizontal and 19 vertical lines forming 361 intersections. Smaller boards (13x13 and 9x9) are also used by beginners or for quick games.

There are several main concepts used in Go: Group of stones, Liberties and Territory :

• Group of stones are stones of the same color, which are horizontally or vertically adjacent to each other:

All white stones forms a single group.
The black stones form two distinct groups.

• Liberties are empty intersections horizontally or vertically adjacent to a stone or a group of stones of the same color:

• The groups of intersections surrounded by stones of one color are territory of the player who uses that color:

A group of 6 intersections at the top left corner is a territory of Whites.

A group of 3 intersections at the right side is a territory of Blacks.

A group of 6 intersections at the bottom left corner is not a territory
of any player because it is not surrounded by stones of one color.

A game begins with an empty board.

One of the players uses black stones and the other player uses white stones. Black plays first.

The players move alternatively placing one stone on one of unoccupied intersections at a time or passing a turn.

There are two restrictions applied to placing stones: Ko rule and prohibition of suicide moves.

If opponent's stone or group of stones remains without liberties as a result of player's move then they are considered captured, removed from the board, and counted towards the surrounding player's score:

The group of black stones at the top left corner has only one liberty. Placing a white stone there results in capturing the entire black group because it remains without liberties. Whites receive 5 points for capturing 5 black stones.

Placing the white stone in specified place does not capture the group of black stones because this group has another liberty. However, Whites can capture the black group on their next turn placing a white stone on the second liberty point of the black group.

A stone cannot be placed on any intersection where it would remain without any liberties or would leave some group of player's stones without liberties, unless placing this stone results in a capturing of some of the enemy stones.

Placing the white stone at the top of the board where the transparent white stone is shown leaves the group of three white stones without liberties. However, this move is allowed because it captures the group of black stones. After removing the captured black stones from the board the group of three white stones at the top gets liberties.

You may not, as a result of a move, return the board to a position that it was at one turn previously.

This situation occurs when a single stone is captured and the opponent has the option to place a new stone on the same point, capturing the same stone that forced the previous capture.

Placing the white stone results in capturing a single black stone. If Blacks were placed a black stone to the same place it would result in capturing the white stone and returning the board to a previous position. The Ko rule prevents such repetition.

To compensate an advantage of the first move, the player who uses white stones can get some amount of additional points, called komi. The value of the komi is agreed by both players before starting the game. The commonly used values are between 5.5 and 7.5. Non-integer values are used in order to avoid draws.

If there is a large difference in playing level between the players then the handicap can be used to compensate the difference: the weaker player plays with black stones and he is allowed to place several stones before his opponent makes his first move. The amount of the handicap stones is agreed by both players before starting the game. The commonly used values are between 2 and 9.

The game ends up when both players passes on their turn.

At this step the players decide, which stones would be certain captured if the game continues. Those stones are called dead, and they are added to the captured stones before counting the final score.

If both players do not agree on which stones are dead, the game resumes.

After coming to the agreement the final score is counted. Scores consist of two elements: the number of empty intersections that your own stones surround (without interference from opposing pieces), and the number of opponent's stones you have captured (including dead ones). Both of these are added together to get your score. A player with a higher score wins the game.