AI GO
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Play Go (Weiqi / Baduk) Online vs the Computer
Play Go — the ancient game also known as Weiqi in China and Baduk in Korea — directly against the computer, free, in your browser, with no download and no sign-up. Choose a 9×9, 13×13 or full 19×19 board; you play the black stones and move first, and the AI plays white. Click an intersection to place a stone: surround empty points to make territory, and surround an enemy group completely to capture it. The full rules are here — captures, liberties, the ko rule, illegal suicide, passing and automatic area (Chinese) scoring — with ghost-stone previews, a move hint, undo, live capture counts and win tracking per difficulty.
How the AI thinks
Go is famously hard for computers: a 19×19 board has hundreds of legal moves each turn and no simple way to score a position, so the game-tree search that powers our Chess and Othello engines does not work here. Instead this opponent uses Monte Carlo Tree Search: for each candidate move it plays out thousands of fast, random games to the end, keeps the moves that tend to win, and searches those lines more deeply — the same core idea behind the modern Go programs that first beat professionals, but running a lightweight random rollout rather than a trained neural network. The whole engine runs locally in your browser in a background worker thread, so nothing is sent to a server and the page stays responsive. It is an enjoyable, genuine opponent for casual and improving players and is at its strongest on the 9×9 board; on 13×13 and especially 19×19 it plays more loosely. We do not claim it plays at professional or top-bot strength.
How to play Go — the rules
- Place and connect. Players alternate placing a stone on any empty intersection; black goes first. Stones never move, but touching stones of the same colour form a group that lives or dies together.
- Liberties. The empty points directly next to a stone or group are its liberties. A group with at least one liberty stays on the board.
- Capture. When you place a stone that removes an enemy group's last liberty, that whole group is captured and lifted off the board. You may not play a stone that would leave your own group with no liberties (suicide) — unless the move captures.
- Ko. You cannot immediately recapture in a way that recreates the previous position; play elsewhere first. The game enforces this for you.
- Passing and the end. Either player may pass instead of playing. Two passes in a row end the game. Because scoring counts the board as it stands, capture any dead stones before you both pass.
- Scoring. Your area is your stones plus the empty points only your colour surrounds; white adds komi (7.5 here) to offset moving second. The larger area wins — the board is shaded so you can see the result.
Tips for beginners
- Start on 9×9. Same rules, far shorter games — you will meet capturing, life-and-death and territory many times per session, which is how the game clicks.
- Make two eyes. A group with two separate internal empty points (eyes) can never be captured. Living groups and killing the opponent's are the heart of Go.
- Corners, then sides, then centre. Territory is easiest to enclose in the corners, harder on the sides and hardest in the open centre — strong openings claim corners first.
- Don't cram. Stones work best with a little space between them; a wall of solid stones surrounds less territory than the same stones spread out.
- Stay connected, keep liberties. Groups low on liberties get captured — count them, and connect weak stones before they are surrounded.
FAQ
Can I play Go online against the computer?
Yes — this page is Go (also called Weiqi or Baduk) played directly against the computer in your browser. There is nothing to download and no account to create: choose a board size (9×9, 13×13 or 19×19), pick a difficulty and whether you play black or white, then click an intersection to place a stone. It works on desktop and mobile.
Is Go the same as Weiqi and Baduk?
Yes — one game, different names: Go (Japanese, from igo), Weiqi (Chinese) and Baduk (Korean) are all the same rules on the same board.
What board size should a beginner use?
Start on the 9×9 board. It uses exactly the same rules as the full 19×19 game but a single game takes a few minutes instead of an hour, so you learn capturing, life and death and territory far faster. The AI is also at its strongest on 9×9, so it makes a better sparring partner there. Move up to 13×13 and then 19×19 as you get comfortable.
How strong is the Go AI?
The Go AI runs a real Monte Carlo Tree Search engine that plays out thousands of random games per move to estimate the best point — the same family of algorithm behind modern Go programs, though without a trained neural network. It is a genuine, enjoyable opponent for casual and improving players and is strongest on the 9×9 board; on 13×13 and especially 19×19 it plays more loosely. We do not claim it plays at professional or top-bot strength. Curious how it decides? Read how the Go AI works →
What are the rules of Go?
Players take turns placing a stone on an empty intersection; black plays first. Stones of one colour that are connected in a straight line form a group, and a group is captured and removed when it has no empty adjacent points (liberties) left. You may not play a stone that would have no liberties unless doing so captures, and the ko rule stops you immediately recapturing to repeat the position. Either player may pass, and two passes in a row end the game. The winner is whoever controls more of the board — their stones plus the empty territory they surround — after adding komi points to white.
What is the ko rule?
Ko is a shape where a single stone can be captured back and forth forever, recreating the same position. The ko rule forbids the immediate recapture: after your stone is taken in a ko, you must play somewhere else for one move before you are allowed to take it back. This game enforces the simple ko rule automatically, so an illegal ko recapture is simply refused.
How is the game scored, and what about dead stones?
The game uses area (Chinese) scoring: your score is the number of your stones on the board plus the empty points that only your colour surrounds, and white receives komi to offset black's first-move advantage. Because there is no penalty for playing inside your own area under Chinese rules, the simplest way to settle the game is to actually capture any dead stones before both players pass — the board is counted exactly as it stands. When both players pass, the territory is shaded and the result is shown.
Is AI Go free, and does it work offline?
AI Go is completely free with no download and no sign-up. The game and the search engine run entirely client-side in your browser, so once the page has loaded it keeps working even without a connection. Your win/loss record is stored locally in your browser. More AI games: AI Chess, AI Othello, AI Checkers, AI Connect 4 or all games.
More AI games on LK Forge
You win!
You controlled more of the board.