|Rekushu is a two-player board game invented in 2006 by John Herr.|
The game Rekushu is played on a square board with orthogonal lines with 20x20 intersections. Boards of other sizes can also be used (e.g. 8x8, 12x12, 14x14, and 18x18).
There are two players having Black and White stones. Stones are placed on the intersections of the grid lines. The squares that the lines make are called tiles.
|The objective of Rekushu is to have claimed more tiles than the opponent when one of the players has no legal moves on his turn.|
Players move alternately, starting from the player having Black stones.
Each move consists of one or two steps: placing a stone and claiming a rectangular region of tiles.
The first step (placing a stone) is mandatory. A stone can be placed on any unoccupied intersection meeting the following conditions:
The second step (claiming a rectangular region of tiles) is optional, i.e. if some region can be claimed then a player can decide whether to do it or not. A rectangular region can be claimed if it meets all of the following conditions:
Below are several examples of the rectangle regions, which are not eligible to be claimed by a player for some reason:
If all the conditions mentioned above are met and the player decides to claim the rectangle, then the player's four stones on the vertices of the rectangle are removed from the board and all the interior tiles of the rectangle are marked with the player's color:
There is one special rule that eliminates an obvious forced draw by the second player. A player is not allowed to make the same type of mirror move consecutively.
There are three types of mirror moves: playing horizontally opposite your opponent (h), playing vertically opposite your opponent (v), and playing at a 180 degree rotation from where your opponent just played (r). A player is allowed to make more than one mirror move in a row, but he cannot make the same type of a mirror move twice in a row.
If a player cannot place a stone because playing on the last intersection would be a mirror violation, then the game immediately ends.