How to play
Go
Go (also called Weiqi or Baduk) is one of the oldest board games in the world. Two players take turns placing black and white stones on the intersections of the lines. The goal is to surround more of the board than your opponent.
Placing stones
- Black moves first; the players alternate placing one stone on an empty point. Stones never move once placed.
- Three board sizes: 9 × 9 (quick, good for learning), 13 × 13 and 19 × 19 (the standard board).
Liberties and captures
- The empty points directly next to a stone (up, down, left, right) are its liberties. Connected stones of one colour share their liberties.
- A move that takes the last liberty of an enemy group captures it: the group is removed.
- You may not play where your own group would have no liberties (suicide), unless the move captures.
The ko rule
A move may not bring the board back to a position that already occurred — for example an immediate recapture in a "ko". Play elsewhere for one move first.
Passing and the end of the game
- When you see no useful move, press Pass.
- Two passes in a row end the game. The site estimates which stones are dead; tap a group to toggle it dead or alive, then press "Confirm".
- When the computer has just passed, your pass ends the game at once, so the site asks first · passed by mistake? Press "Undo" during scoring to go back to the game.
- During scoring, a faded stone with a cross is dead (it counts as the other side's area); a small square marks that colour's area.
Scoring
- Area scoring (Chinese rules): your stones on the board plus the empty points only you surround (dead stones count as the other side's area).
- White receives komi of 7.5 points for moving second, so there are no draws.
- The captures shown on the player cards are for information only; they are not points under area scoring. The result shows each score as stones + area, and the margin.
Computer levels
| Easy | Thinks briefly and makes mistakes often. Start here on 9 × 9. |
|---|---|
| Medium | Captures and escapes ataris; you need good territory. |
| Hard | Uses its full thinking time with many simulated games; strongest on 9 × 9. |
On this site: tap an intersection to place a stone. The small ring marks the last move. On a touch screen, 13 × 13 and 19 × 19 boards take a first tap to aim and a second on the same point to place (a tablet with wide points places at once). Tap a forbidden point (ko, suicide) and the site tells you why.