0-black0-black 0-white0-white 2-black2-black 2-white2-white 3-black3-black 3-white3-white 4-black4-black 4-white4-white 5-black5-black 5-white5-white 6-black6-black 6-white6-white 7-black7-black 7-white7-white 8-black8-black 8-white8-white 9-black9-black 9-white9-white congrats_loseThanks for the game! congrats_tieThanks for the game! congrats_winCongratulations! hintHint ia_passCrazy Stone passes illegal_okIllegal ko! illegal_suicideIllegal suicide! lose_capture_exYou captured the stones, but you could have used fewer moves. Please, try again. okOK passPass playLet's play recommended (recommended) resetReset text_handSelect handicap and your color undoUndo win_capture_exCongratulations! winorlose_loseYou lose winorlose_tieIt's a tie winorlose_winYou win

Welcome to the World of Go

a game of Go in progress

The game of Go is a traditional board game from Asia. If you don't know how to play, this page will teach you the rules, and let you play your first games against the computer.

Overview of the Game

The game of Go is played on a grid. Experienced players usually play on a 19×19 board. For this introduction, to make things simpler, we will use a 5×5 board instead:

. . . . .. . . . .. . . . .. . . . .. . . . .

The game is played by two players, Black and White, who take turns placing stones on the grid. Stones are placed on line intersections. Black plays first. Below is a possible sequence of moves:

. . . . .. # . . .. . . . .. . . . .. . . . .
. . . . .. # . . .. . . O .. . . . .. . . . .
. . . . .. # . . .. . . O .. # . . .. . . . .

Stones of the opponent can be captured by surrounding them. The capture rule will be explained in more details later.

Instead of playing a stone, a player can also pass. The game ends when both players pass in a row.

There are some variations of how the final score is counted. For this tutorial, we will use the simplest rule: the winner is the player with the highest number of stones on the board. For instance, in this position, White and Black passed. White has 14 stones on the board, and Black has 7 stones. So White won:

O . O . OO O O O OO O O O OO # # # ## # . # .

Capturing Stones

It is possible to capture a stone by removing its liberties. The liberties of a stone are empty adjacent points:

. . . . .. . m . .. m O m .. . m . .. . . . .
. . . . .. . . . m. . . m O. . . . m. . . . .
. . . m O. . . . m. . . . .. . . . .. . . . .

Note that points in diagonal don't count as liberties. Only points that are horizontally or vertically adjacent are liberties.

A stone is removed from the board when it has no liberties any more:

. . . . .. . # . .. # O . .. . # . .. . . . .
. . . . .. . # . .. # O # .. . # . .. . . . .
. . . . .. . # . .. # . # .. . # . .. . . . .

When stones of the same color are adjacent, they form a string. Stones of a string cannot be captured individually. The whole string is captured when all its liberties are removed. Here are some examples of strings and their liberties:

. . . . .. m m . .m O O m .. m m . .. . . . .
. . m O O. . . m O. . m O O. . . m m. . . . .
. . m O O. . m O m. . m O O. . m O m. m O O O

Strings are connected horizontally and vertically, but not diagonally. Here is how Black captures one of two strings:

. # # . .# O O . .. # # O .. . . O .. . . . .
. # # . .# O O # .. # # O .. . . O .. . . . .
. # # . .# . . # .. # # O .. . . O .. . . . .

Now, it is your turn! You can tap or click on the board to play. Try to capture all the white stones with as few moves as possible!

# O . O ## O O O #. # O # .. . # . .. . . . .
. . . . .. . . . .. O . . .. O O . .. . . . .
. . . . .. . O . .. O . . .. . . . .. . . . .

Illegal moves

A move may not create a string without any liberty. For instance, in this position, Black is not allowed to play at the marked points:

m O # # #O O O # mO m O O O# O . # ## m O # .

Note that you can create a liberty with a capture. This sequence is legal:

. . # # #O O # O #O . O O #O O # # #. O . # .
. . # # #O O # O #O # O O #O O # # #. O . # .
. . # # #O O # . #O # . . #O O # # #. O . # .

Without the capture, Black's move would have been illegal:

. . # # #O O # O #O m O O #O O # . #. O . # .

The last rule is the rule of Ko. In the position below, after Black captures the stone, White would like to capture Black's previous move by playing at the marked point:

# # O O O# O . O .# # O O O# . # O O# # # # #
# # O O O# O # O .# # O O O# . # O O# # # # #
# # O O O# m # O .# # O O O# . # O O# # # # #

Re-capturing at the marked point would re-create the initial position. Then Black may wish to capture again, and the game would be stuck in a loop. In order to prevent such a never-ending cycle, the Ko rule forbids any move that re-creates a past configuration of the whole board. So the marked move is illegal.

Let's Play!

Now, you know the rules of Go. You can start having fun playing against the computer!

In order to give you a better chance to win, you can play with a handicap. The computer is rather strong, so you might not be able to win easily. To make the game more balanced, the weaker player can start with more than one stone on the board. When given such handicap stones, winning is easier, and games against a stronger opponent become more exciting.

The complexity of 5×5 Go is very limited. When you feel like it, you should move on to 9×9, where you'll better appreciate the beauty of the game.

Let's Play 9×9 Games

What's Next?