How to play Go
Play Go online on 9×9, 13×13 or 19×19. Captures, suicide and ko follow the rules; after two passes the game is scored by area under Chinese rules with 7.5 komi, and dead stones can be marked. Play the computer on 9×9 and 13×13, or two players; undo and SGF download. Free, no ads.
- Controls
- Click an intersection to place a stone, or pass; before a game, choose the board size and the computer or two players
- Features
- Captures and capture counts, ko and suicide checks, the last move marked; dead stones estimated at the end and adjustable; area scoring; undo and SGF download
- Processing
- Runs in your browser, the computer player included; nothing is uploaded
- Choose a board (9×9 to learn, 19×19 is the full board) and an opponent. Against the computer, choose 9×9 or 13×13; you play black and move first.
- Click an intersection to place a stone. Stones without liberties are captured; you may not play where your stone would have no liberties without capturing, nor retake a ko at once.
- After two passes in a row the game ends and scoring begins: likely dead stones are marked, click a group to toggle it between dead and alive, then confirm to see the result under area scoring.
FAQ
Which rules decide the winner?
Chinese area scoring: each side counts its living stones plus the empty points surrounded only by its own stones, and white receives 7.5 points of komi. Dead stones count for the other side, so check the dead-stone marks before you confirm.
How strong is the computer?
It uses Monte Carlo tree search: for every move it plays out tens of thousands of games in your browser and picks the move it is most sure of; higher levels think longer. It beats players who have just learned the rules but is no match for dedicated Go software, so it suits learning and practice. 19×19 is for two players only: the board is too big for the computer to find sensible moves in a browser.
How is ko handled?
After you capture a single stone, your opponent may not capture back at once, since that would repeat the previous position; they must play elsewhere first. Longer cycles are not handled specially.
Can I save the game?
Yes, download it as an SGF file, which common Go programs open.
Do I need an account or a connection?
No. The game and the computer’s thinking run in your browser, and nothing is uploaded.