Each move does one thing: put a stone on an empty intersection. It does not move again. What follows is the order this board actually enforces: where a stone may go, when a group is captured, which moves are rejected, and how the three scoring methods count a finished game. Star points are marked intersections. They grant nothing extra.
Stones go on intersections, not inside squares
Black plays first, then the players alternate. A stone sits where two lines cross, not in the middle of a square. Once played, it stays there for the rest of the game. Versus AI you may take Black and move first, or White and move second. On the same screen, and in an online room, the two players simply alternate, and Black still moves first.
Nothing requires the first stone to occupy a particular point. An intersection that already holds a stone cannot take another.
Liberties, connection, and capture
A liberty is an empty intersection directly above, below, left, or right of a stone. A diagonal touch does not connect stones and is not a liberty. Same-colored stones joined orthogonally form one group and share every liberty around it. When the opponent fills the last liberty, the whole group leaves the board at once.
Count liberties for the group, not for a single stone. A group with exactly one liberty is in atari. Atari does not capture it. The group comes off only when the opponent fills that last liberty with a legal move.
Two moves this board rejects: suicide and a repeated position
A move is suicide when it captures nothing and leaves your own group with no liberties. This board will not play it. A stone added inside a surround is legal only if it gives the group a liberty or captures opposing stones at the same time.
Ko is positional superko. You may not make any earlier position of this game appear again. In a single ko you cannot recapture on the same point immediately. Play somewhere else first; after the opponent answers, you may come back.
If a point will not accept a stone, it is occupied, the move would be suicide, or it would restore a position that has already occurred.
After two passes: mark dead stones, then score
Pass hands the turn to the opponent. The game continues. If the opponent then plays a stone, the pass count returns to zero. After the two players pass on consecutive turns, the board enters dead-stone marking. It does not announce a winner yet. Pressing Score before those two passes only asks you to pass first.
Click one stone and the whole orthogonally connected group is marked dead. Click it again and the mark comes off. Clicking an empty intersection does nothing.
Versus AI, and on the same screen, the device you are using presses Confirm. In an online room both players must press Confirm. If either player changes a dead-stone mark, both confirmations are cleared.
Resume clears the marks and returns to play. Two consecutive passes are required again before marking can start over.
Empty points are shared by all three methods. A connected region of empty intersections that touches only one color counts for that color. A region that touches both colors counts for neither. This board does not apply a separate seki exception. An eye that touches only one side still counts as empty points for that side.
| Item | Chinese | Japanese | Korean |
|---|---|---|---|
| Method | Area | Territory | Territory, same formula as Japanese |
| Living stones on the board | Count | Do not count | Do not count |
| Empty points touched by only one color | Count for that color | Count for that color | Count for that color |
| Prisoners | Not added | Count for the capturer | Count for the capturer |
| Dead stones | Remove them. The point left behind is empty and goes to the side that surrounds it. Do not add the stone again. | Count for the opponent. If only the opponent surrounds the point left behind, count that empty point too. | Same as Japanese |
| Komi | White +7.5 | White +6.5 | White +6.5 |
Chinese rules are the default. After dead stones are removed, each side scores living stones still on the board plus empty points surrounded only by that side. Prisoners are not added, because living stones are already on the board. A dead stone is not scored again as a stone; the point it leaves is empty and belongs to the side that surrounds it. White receives 7.5 komi.
Japanese rules and Korean rules use one formula. Living stones on the board are not counted. The score is empty points, plus prisoners, plus the opponent’s dead stones. White receives 6.5 komi. One dead stone meets two different counts: the stone itself is a prisoner for the opponent, and the intersection it leaves is an extra empty point if only the opponent surrounds it. That is not the same stone added twice. On this board the Japanese and Korean names share that formula.
Both 7.5 and 6.5 include a half point, so the two totals cannot tie. A game that ends by scoring is not a draw. The rules choice sits in the versus-AI sidebar and is stored on this device. Same-screen play has no rules control; it scores with whatever was last chosen versus AI, and that is Chinese rules if you have never changed it. An online room ignores that choice. The server always uses Chinese area scoring, with 7.5 komi for White.
An online room can also end without scoring. Resign gives the game to the opponent. Draw offers a draw; if the opponent accepts, the game is a draw, and if they decline, play continues. Same-screen play and versus AI have neither button.
9×9, 13×13, and 19×19 share the placement rules
All three sizes use Black first, intersections, orthogonal liberties, no suicide, positional superko, and the dead-stone ending above. Only the number of intersections changes: 81, 169, and 361. Star points move with the size. They do not change what is legal or what can be captured.
Versus AI and on the same screen, the sidebar can change the size. An online room’s size is chosen when the room is created and does not change after someone joins.
Questions
Do stones connect diagonally?
No. Only stones touching above, below, left, or right form one group. Two stones that meet at a corner are still two groups. Liberties and captures follow the same rule.
I surrounded a group. Why is it still on the board?
It still has a liberty. Liberties hide on the outside of a connected stone, or they are shared through an orthogonal link. One adjacent empty point is enough to keep the group on the board.
Is a pass the same as resigning?
No. Pass only skips the turn. Two consecutive passes open dead-stone marking, and Resume returns to play if you disagree. In an online room, Resign is a different button. It ends the game immediately and does not score.
Do 9×9, 13×13, and 19×19 use different rules?
Placement is the same: Black first, intersections, liberties and capture, no suicide, positional superko, then dead stones after two passes. The intersection count is what changes. Whether the finish uses Chinese, Japanese, or Korean scoring depends on the versus-AI choice and on whether the game is an online room, not on the board size.
How do Chinese, Japanese, and Korean scoring differ here?
Chinese area scoring counts living stones plus empty points you alone surround. Prisoners are not added, and White receives 7.5 komi. Japanese and Korean territory scoring count empty points, prisoners, and the opponent’s dead stones. Living stones on the board are not counted, and White receives 6.5 komi. On this board those two names run the same formula.
Which scoring method do online rooms and same-screen games use?
Online rooms are fixed to Chinese rules, with 7.5 komi for White, and both players must confirm the dead stones. Same-screen play has no rules control. It uses the method last chosen versus AI on this device, which is Chinese rules if you have never changed it.
Can a half-point komi still draw?
Not when the game is scored. 7.5 and 6.5 keep the totals from matching. An online room can still draw if both players accept Draw, or it can end by Resign, without counting the board.
