The board and the stones
Go is played on a grid of lines. Stones go on the intersections, not in the squares. Black plays first, then players alternate, placing one stone per turn. A stone never moves once played — it either stays there for the rest of the game or it is captured and removed.
The full board is 19×19, but beginners should start on 9×9. A nine-line game takes ten minutes, contains every rule and every important idea, and finishes before the position becomes overwhelming. Thirteen is the natural next step.
Liberties: the one idea everything rests on
A stone's liberties are the empty intersections directly next to it — up, down, left, right. Diagonals do not count. A stone in the middle of the board has four liberties, one on the edge has three, one in the corner has two.
Stones of the same colour that are directly connected form a group, and a group shares its liberties. A group with liberties is alive on the board. A group whose last liberty is filled by the opponent is captured and removed immediately.
Capturing
To capture, surround. You do not need to enclose a group in a ring — you need to occupy every empty point adjacent to it. A group pressed against the edge needs fewer stones to capture, which is why the edges and corners are easier to hold than the centre.
A group reduced to one liberty is said to be in atari. It is about to be captured, and its owner must either add a stone to extend its liberties, capture something in reply, or accept the loss.
The two rules that stop chaos
No suicide. You may not place a stone on a point where it would have no liberties, unless that same move captures an enemy group and thereby gives your stone room to breathe.
The ko rule. You may not immediately recreate the exact board position your opponent just left. Without this rule, single-stone captures could repeat forever. In practice it means that after a one-stone capture, the opponent must play elsewhere for one move before recapturing.
Two eyes: how groups become permanently safe
An eye is an empty point completely surrounded by one colour. A group with two separate eyes can never be captured, because the opponent would have to fill both, and filling the first would be suicide.
This is the single most important concept in go and it is not a rule — it follows from the rules. Every fight ultimately asks the same question: can this group make two eyes, or can it connect to a group that already has them?
Passing and ending the game
If you have no useful move, you pass. When both players pass in succession, the game is over. There is no checkmate and no capture of a king; the game ends by agreement that nothing more is worth playing.
Counting
This board uses area scoring, also called Chinese counting: your score is the number of stones you have on the board plus the number of empty points completely surrounded by your colour. White then adds komi — a compensation for moving second, set to 5.5 on 9×9 and 6.5 on larger boards. The half point guarantees there are no draws.
The Count button shows the score as it currently stands without ending the game, which is a useful way to learn what the numbers look like as a position develops.
Do not fill your own territory
Once a group is safe, adding more stones inside your own area costs you nothing under area scoring but wastes moves. Play elsewhere — there is nearly always a bigger point.
Your first game in five ideas
- Play in the corners first, then the sides, then the centre. Corners need fewest stones to surround territory.
- Do not play on the very edge early. The first line has almost no territory value.
- Keep your stones loosely connected. Two stones a knight's move apart usually cannot be cut.
- When a group is in atari, deal with it or accept losing it — do not add one stone at a time to a lost cause.
- Aim for two eyes with every group you care about.