Play Go Online — 9×9, 13×13 & 19×19 Boards
The deepest board game in the world, free in your browser: strict liberty and capture engine, two-eye life-and-death, superko enforcement, Chinese and Japanese scoring with komi.
✨ Why play here
📏 Three board sizes
9×9 for fast fundamentals, 13×13 for middle-game practice, 19×19 for the full strategic canvas.
⚖️ Rules done properly
Liberties, captures, suicide prohibition, ko and superko are all enforced exactly — no ambiguous positions.
🧮 Both scoring systems
Score by Chinese area or Japanese territory rules, with standard komi so White is fairly compensated.
🏆 Ladder & replays
Rated games feed the global ladder, and every game can be replayed stone by stone.
📖 The rules fit in a paragraph
Players alternate placing stones on empty intersections. A stone or connected group's empty adjacent points are its liberties; a group whose last liberty is filled is captured and removed. You may not play a stone that would leave its own group with no liberties (suicide), and you may not recreate the previous whole-board position (ko). When both players pass, the game ends and the larger total of territory (plus stones or prisoners, depending on ruleset) wins, with komi added to White's score to offset Black's first-move advantage.
The ideas that make it deep
- Two eyes live — a group with two separate enclosed points can never be captured. All life-and-death reading flows from this.
- Corners, then sides, then centre — territory is cheapest to enclose where the board edges help you.
- Connect your stones, cut your opponent's — strength in Go is connectivity; most middle-game fighting is about who gets cut.
- Ko fights — because of the ko rule, some captures turn into whole-board negotiations where every threat on the board becomes currency.
❓ Frequently Asked Questions
Which board size should a beginner start on?
Start on 9×9. Games take ten minutes, every stone matters, and the core ideas — liberties, capturing, making two eyes — appear immediately. Move to 13×13 once captures feel natural, and to the full 19×19 board when you want real opening strategy.
What does it mean for a group to be alive?
A group that contains two separate enclosed empty points — two eyes — can never be captured, because the opponent cannot fill both eyes at once. Nearly all life-and-death fighting reduces to whether a group can make two eyes before being surrounded.
What is the ko rule?
Ko forbids a move that would recreate the exact previous board position. After a ko capture, the opponent must play elsewhere first — a 'ko threat' — before recapturing. This engine enforces positional repetition (superko) automatically.
What is the difference between Chinese and Japanese scoring?
Chinese rules count your stones on the board plus your surrounded territory; Japanese rules count territory plus captured prisoners. Results almost always differ by at most a point, and both systems are supported here along with standard komi compensation for White.