Go is one of the oldest board games in the world — over 4,000 years old. You play Black ⬛ against the AI (White ⬜). Your goal is to surround more territory than your opponent by the time both players pass.
Tap any empty intersection on the 9×9 grid to place a black stone. Stones never move once placed — they stay on the board unless captured. Black always moves first, then players alternate turns.
Every stone needs at least one adjacent empty space (called a liberty) to survive. When you surround all the liberties of an enemy group, those stones are captured and removed from the board. Each captured stone earns you 1 point.
A group of your stones with two separate internal empty spaces (eyes) can never be captured — your opponent can never fill both at once. Building two eyes is the key to making your groups permanently safe.
No suicide: You cannot place a stone where it would have zero liberties — unless that move captures enemy stones first. Ko rule: You cannot make a move that returns the board to its exact previous state, preventing infinite capture loops.
When you have no useful moves left, tap Pass. When both players pass consecutively, the game ends and scoring begins.
Your final score counts territory (empty intersections fully enclosed by your stones) plus captures (enemy stones removed). White receives 6.5 komi (bonus points for going second), which also eliminates ties. The higher total wins.
The difficulty setting controls how deeply the AI thinks — from pure random moves at Beginner to thousands of strategic simulations at Cyborg ☠. Start on Beginner to learn the flow, then work your way up as you improve.
Play Go 9×9 free online — no download required, no sign-up needed. This browser-based version uses a Monte Carlo Tree Search (MCTS) AI engine that simulates thousands of possible game outcomes to find the strongest move. On a 9×9 board, games are fast and tactical — perfect for learning Go fundamentals before moving to larger boards.
The daily challenge resets every midnight — the same opening seed for all players worldwide. Beat the AI, share your score, and challenge friends with a direct link to your exact game setup.
A 9×9 board keeps games to minutes instead of hours while preserving the life-and-death reading that makes Go what it is — it is the size real Go schools start students on. The MCTS opponent reads noticeably deeper at higher levels. For a gentler territorial fight, Ultimate Reversi flips discs instead of surrounding stones.
I built this game because Go is one of the first games an AI was ever seriously trained on, and that history is personal to me — reading about a computer beating a human expert is what pulled me into playing Go online in the first place. The machine-versus-mind story hooked me before the stones themselves ever did. So putting a Go AI on this site felt like closing a loop that started in a news article years ago: the game that taught machines how to think, now running its own small thinking machine quietly inside your browser tab, waiting for your first move.
That AI is where my central design decision lives. The engine runs Monte Carlo tree search, and MCTS has an appetite problem: give it more playouts and it plays stronger, but it also takes longer, and an opponent that stalls kills the fun far faster than an opponent that occasionally blunders. My call: cap the playouts by a per-move time budget, enforced at every difficulty level. The AI thinks exactly as long as feels responsive and not one second more — strength scales through how efficiently the engine spends its fixed budget, not through how long it keeps a human being waiting. A browser Go opponent should feel like a partner across a small board, not a server farm you've submitted a batch job to.
The 9×9 board is the right arena for that philosophy, and it's also where the classic beginner mistake gets punished quickest: getting corner life-and-death wrong. Here is the rule that decides those fights — a group needs two real eyes to live. Two, genuinely separate, actual eyes. Not one big space that looks like it could someday become two; not a false eye your opponent can eventually fill from the outside. And corners, which beginners flock to because territory comes cheap there, give the least room of anywhere on the board to build those two eyes. So the pattern repeats endlessly: a corner group that looked snug and settled turns out to have one eye and a wish, and it dies wholesale, taking a quarter of the board's hopes down with it.
The discipline: count eyes before committing more stones to any group, and count honestly — a real eye is a point your opponent can never fill. And the companion sin, so common it physically hurts to watch: don't fill your own eye space. Players cram defensive stones into the exact points their group needed for its second eye, executing their own group with steady, well-meaning hands.
Nine-by-nine keeps the games short and the lessons fast. The daily position lands at midnight, same for everyone. Two eyes. Always two eyes. The machine across the board already knows.