Ludii Portal

Offshore is a territorial game where territory is based on 3 pillars: -- Territory defined by the convex hulls of groups, -- Group expansion limited to those groups that are not larger than the count of the current number of friendly groups. -- The capture of enemy groups by expanding one's territory to encompass them. A further minor point is that placement into enemy territory is restricted, thus preventing suicide placements, and indeed for standard play, preventing any expansion into the territory at all. Some of the implications are: -- groups can be captured from two sides, no need to surround. -- to expand or merge groups, one must first have played enough isolated stones during the game. This rule prevents the game from being a simple race to cut off large corners. -- capturing a group therefore also reduces the captured player's expansion potential due to loss of a group, in addition to the reduction in playable space. -- merging groups is a powerful key type of move that creates strategic focus, but also reduces future growth potential by reducing the group count. -- cells adjacent to stones along the edges of opponent's territory are likely to remain open for play, but care is needed to ensure that, when placing stones there, they are (or can be) connected to regions where the opponent is less able to expand his territory. The game was inspired by investigating possible new ways of defining territory and capture.

Rules

Definitions:
-- Each of a player's stones belongs to exactly one group.
-- The group it belongs to contains all the stones that connect to it by virtue of being next to one another (across an edge).
-- A player's territory is the union of all the cells that are within the convex grid-oriented hulls of the player's groups.

In simpler language:
Imagine a line of cells that goes through just one stone of a group and leaves the rest of that group to one side. Surround the group with six of these lines and they will exactly contain all the territory of the stones of that group. A player's territory is then the combined territory of every group, counting cells only once where any of the group territories overlap.

-- A player's score is the number of empty cells in their territory.

Play:
The mover places a stone onto an empty site, with the following two limitations:
1) No placing in the opponent's territory.
2) No placing next to a friendly group that has more stones than there are friendly groups.
(Note that the resulting size of a group is irrelevant.)

After the placement, every opponent's group that lies completely within the mover's territory is removed.

Passing is voluntary.
When both players pass consecutively, the higher score wins. In case of a tie, the last to play wins.

Various boards are optional.
Weak Territory, allowing placement next to a friendly group in enemy territory is optional.