Summary

Meridians is an abstract strategy game for two players. It has a
territorial nature, but the goal is to annihilate the opponent's stones.

Meridians is named after the meridian system, a concept in traditional
Chinese medicine conceptually similar to the circulatory system.

Kanare Kano designed Meridians in March of 2021.

Components

A centerless hexagonal board tessellated with triangles. The regular
size board has six intersections along two sides and seven intersections
along the other four sides.

A sufficient number of stones of two colors.

Definitions

Group: Like-colored stones adjacent to each other. Singletons are
considered groups of size 1.

Path: An uninterrupted straight line of at least one empty intersection
connecting two different but similar-colored groups.

Dead Group: A group which has no path connecting it to another group.
Gameplay

The player controlling the light colored stones moves first, with turns
alternating afterwards.

On each player's first turn, the active player must place a stone of
their color onto any empty intersection. On the second turn, players
place according to the rules below, but may not place their second stone
adjacent to their first.

During each subsequent turn:

1. If the active player has no stones on the board, they lose.

2. The active player removes all of the opposing color dead groups from
   the board. Skip this step if the opponent has taken fewer than two
   turns.

3. The active player must place a stone of their color onto any empty
   intersection that is on a straight line from an existing friendly
   stone, such that there are no different colored stones between them.

Passing is not allowed, but step 3 will be skipped if the active player
has no legal move or if the opponent has no stones remaining.

Because this game tends to continue after the winner is obvious, it is
recommended that the losing player resign once each other's territory
has been established. Territories are empty points surrounded by groups
that cannot be annihilated by the opponent's stone invasion. See the
rulebook for more details.

Pie rule (Optional)

To mitigate the first-mover advantage, pie rule can be used as an
option; BoardGameArena implementation requires that the opening rule
setting be changed to pie beforehand.

When using this rule, the first player places one stone of each color on
the board at the beginning of the gamea and the second player decides
which color to play (light is always first). Thereafter, the game is
played as usual.

The use of the pie rule is recommended between players with some
experience.
