The aim of Go is to 

control more territory

 and capture more stones than your opponent.

Go is played on a grid. Stones are 

placed on the intersections

 of the lines. Black plays first.

During the game, one or more stones are captured when they are 

completely surrounded

 and have no empty adjacent points (liberties) left.

If a move would recreate the 

same board position

 that existed before the opponent’s previous move, that move is not allowed. This is called the 

ko rule

. It prevents endless repetition.

A 

player may pass

 instead of placing a stone. When both players pass consecutively, the 

game ends and the board is scored

. A player’s score is the number of empty points surrounded only by that player’s stones, plus the number of captured stones. Dead stones are removed before scoring. The player with the higher score wins.

There are currently 

four different board sizes

 available: the three standard sizes—9x9, 13x13, and 19x19—and a special 15x15 board.

To change your preferred board size, click the gear icon in the center of the screen to open 

Chat and Game Settings

.

You can change the 

game’s graphics

.

To do this, 

press F3

 while playing a match, or enable the option in the game’s Chat and Game Settings dialog.

Komi is 

compensation

 given to the white player because White moves second. The komi can be set to 4.5, 5.5, 6.5, or 7.5.

You can save your games after they have finished by pressing the 

SGF Export button

.

To save the file for future use, you will need to 

copy and paste the exported data

 into another application, such as a text editor or an SGF editor.

To activate full-screen mode, 

press F11

 on your keyboard after starting the game.