Epaminondas - game

Epaminondas starting position. Row A is Black's goal; row Z is White's.
Years active	1975 to present
Genre(s)	Board game Abstract strategy game
Players	2
Random chance	None
Skill(s) required	Strategy, tactics
Synonym(s)	Crossings

Epaminondas is a strategy board game invented by Robert Abbott in 1975. The game is named after the Theban general Epaminondas, known for the use of phalanx strategy in combat, and the concept of the phalanx is integral to the game.

Epaminondas was originally introduced in Sid Sackson's A Gamut of Games as Crossings. While the original version used an 8x8 checkerboard, the current game uses a 12x14 board and different rules for capture. When published, it claimed to be one of the first modern games to acknowledge the name of its inventor in its rules.

Rules

Objective

If, at the start of their turn, a player has strictly more pieces on their opponent's home row than the opponent does, that player wins. To clarify, if Black has more pieces on row A than White does on row Z at the beginning of Black's turn, Black wins. If White has more pieces on row Z than Black has on row A at the beginning of White's turn, White wins. This allows an opponent the chance to capture some of the offending stones on the turn after an incursion, or to counterattack on the opposite side of the board.

Phalanx

In the game, a phalanx is defined as a horizontal, vertical, or diagonal line of stones of the same colour, with no empty spaces or enemy stones between them. An isolated stone could be considered a phalanx of one, but officially all phalanxes consist of two or more stones. Note that a stone may belong to more than one phalanx, depending on the direction considered.

Piece movement

• White moves first; turns alternate afterwards.
• A player may move a single piece one space in any direction, as a king in chess.
• A player may, instead, move a phalanx any number of spaces equal to or less than the number of pieces in the phalanx. They must all move in the same direction, and that direction must be along the line of the phalanx. A phalanx of three stones along a diagonal may move three, two, or one spaces along that diagonal, and so on.
• A player does not have to move an entire phalanx; they may split it into two pieces, as long as the subset moved is continuous and only moves, at most, as far as its length.
• A phalanx may not move through or across pieces of the same colour.
• The head piece of a (two-piece or more) phalanx may land on a single enemy stone; it is captured. Similarly, any phalanx's head piece may land on the head of an enemy phalanx whose size is strictly smaller; the entire enemy phalanx is captured.
• Capture is not compulsory.
• To keep the game from ending in a draw due to copycat moves, there is an additional rule: no player may move a piece onto their opponent's home row if that move creates a pattern of left-to-right symmetry on the board.