Crossings (game)

Crossings is a two-player abstract strategy board game invented by Robert Abbott. The rules were published in Sid Sackson's A Gamut of Games. Crossings was the precursor to Epaminondas, which uses a larger board and expanded rules.

Equipment

 * 1 8x8 gameboard
 * 32 stones (16 of each color)

Setup
This is the starting position of Crossings.

Object

 * Cross one stone to the opponent's end of the gameboard.

Turns

 * Play alternates with each player making one movement on a turn.
 * Red takes the first turn.

Movement
A group is a series of one or more same-colored stones adjacent to one another in a line. (diagonal, horizontal, or vertical) A stone may belong to one or more groups.


 * A player may move a single stone, an entire group, or a subgroup.
 * A group consisting of a single stone may move one space diagonally or orthogonally into an empty square.
 * A group must move along the line which defines it. It may move a number of spaces equal to the number of pieces in that group.
 * When part of a group is moved (a subgroup), it must move along the line which defines it. It may move a number of spaces equal to the number of pieces in the subgroup.
 * When a subgroup is moved it must involve one of the end stones.
 * Pieces may not move onto an occupied square.

Capturing an enemy stone

 * If the first stone in a moving group encounters a single enemy stone, the group's movement stops there, and the enemy stone is captured.
 * If the first stone in a moving group encounters an end stone of an opponent's group, it can capture that stone if the opponent's group is smaller. The turn ends.
 * If it cannot capture the end stone because the opponent's group is the same size or larger, it is not allowed to move on to that square.

End of the game

 * A player potentially wins the game if they get a stone on the home row, or row farthest from their side. If their opponent cannot get a stone of their own onto the first player's home row in their next move, the first player wins. Otherwise, those stones are "locked"; they cannot be moved or captured. The next attempt at crossing, as this is called, will determine the winner (unless it, too, is immediately followed by a counter-crossing, and so on.)
 * The game is a draw if no player can complete the objective. Draws are rare.