How to Play
On a player's turn, the player places one stone (stán) on a square on the game board.
Stones (stánas) must be placed within the square, not on the intersections as in Go.
Stones may be placed on any empty square, either standing alone or adjacent to another stone of either color (creating a heorr or "hinge").
Passing rules
When playing with Special Stones, the opposing player may have viable moves remaining while the active player may not. When this occurs, the active player must pass.
If the opposing player uses a Thunder-stone, stones are removed from the board so new moves may become available on the player's next turn.
Placement limitations
Stones may have no more than three hinges; the fourth side must always remain free.
Stones may not be placed such that four hinges are created immediately.
The edge of the board counts as one hinge; corners count as two because they border two edges.
Play continues until no more viable moves remain.
Thunder-stone rules
Players each have one thunder-stone (Þunor-stán), which may be placed on the board during their turn instead of a regular stone.
Thunder-stones are the exception to the four hinge limitation. This is because, when placed, a thunder-stone removes any and all stones orthogonally adjacent to its position, whether they belong to the player or the opponent.
Stones which have been removed from the board are returned to the respective players and do not count as captures or contribute to scoring in any way.
After placement, thunder-stones hinges and scoring are treated the same as normal stones.
Woden-stone rules
Players each have one Woden-stone (wóden-stán), which may be placed on the board during their turn instead of a regular stone.
Unlike standard and thunder-stones, which are placed on an open square, players use the Woden-stone to replace one of their opponent's stones already on the board.
Being able to swap out an opponent's stone can create unique scoring and blocking opportunities, so waiting to use the Woden-stone until later in the game may offer greater strategic advantage.
After placement, Woden-stones are scored the same as normal stones.