## 13 April 2017

### Crossings

Crossings is a strategy board game for two players invented by Robert Abbott. Crossings is a precursor of Epaminondas, which uses a larger board and expanded rules.

Rules

The game uses a $8 \times 8$ board with $16$ pieces of each color. The goal is to cross a piece until the end of the opponent's back rank. The game is played by turns, each player makes a move per turn. The red pieces start.

A phalanx is a set of one or more adjacent pieces of the same color in a row (horizontally, vertically or diagonally). A piece can belong to one or more phalanxes.

A player can move a piece, a whole phalanx or a sub-phalanx.

A phalanx consists of a single piece may move a space horizontally, vertically or diagonally on an empty square. A phalanx should move through the line that defines it. It can move a number of times equal to the number of pieces of that phalanx.

When part of a phalanx is moved (sub-phalanx), it also has to move along the line that defines it. It can move a number of times equal to the number of pieces of that sub-phalanx. When a sub-phalanx is moved, it must involve one of its final pieces.

The pieces can not move to a busy square.

If the first piece of a moving phalanx finds a single piece of the opponent player, the movement of the phalanx ends and the opponent's piece is captured.

If the last piece of a moving phalanx finds the final piece of the opponent's phalanx, it can capture that piece if the phalanx of the opponent is smaller; the turn ends. If you can not capture the piece because of the opponent's phalanx is of the same size or bigger, you may not move to this square.

A player wins the game if one of his pieces reaches the first line of the side of the opponent player or the more distant line on his side. If your opponent can not get a piece in the first line of the first player in the next turn, then the first player wins. Otherwise, these pieces will be "locked" and can not be moved or captured. The next attempt to crossing, as it is called, will determine the winner (unless it is also immediately followed by a counter-crossing, and so on). The game is a draw if no player reaches the goal. The draws are very rare.