Nine Mens Morris

Nine Mens Morris is an abstract strategy board game for two players. Its origins are ancient, with evidence of play dating back to the Roman Empire and possibly earlier in Egypt. The game is also known as Mills, Merels, or Morelles. The board consists of a square grid with three concentric squares connected by lines at the midpoints of each side, forming 24 intersection points. Each player begins with nine pieces, traditionally black and white, which are placed on the board. The objective is to reduce the opponent’s pieces to two or to block all of their remaining pieces from moving. A key mechanic is the formation of a “mill,” a straight line of three of a player’s own pieces on adjacent connected points. Forming a mill allows the player to remove one of the opponent’s pieces from the board, provided that piece is not part of a mill itself. The game proceeds through three distinct phases: placement, movement, and the flying phase. The placement phase involves players alternately placing their nine pieces on any empty intersection. Once all pieces are placed, the movement phase begins, where players slide one of their pieces along a line to an adjacent empty point. When a player is reduced to three pieces, the flying phase is entered, allowing that player to move any piece to any empty point on the board, regardless of adjacency. The game ends when a player has only two pieces left or cannot make a legal move.

Gameplay proceeds in three sequential phases. In the placement phase, players take turns placing one of their nine pieces on any empty intersection point on the board. A mill is formed when three of a player’s pieces occupy a straight line of three connected points. Upon forming a mill, the player immediately removes one opponent piece from the board, selecting any opponent piece that is not part of a mill. If all opponent pieces are in mills, the player may remove any piece. After all 18 pieces are placed, the movement phase begins. In this phase, a player selects one of their own pieces and moves it along a drawn line to an adjacent empty intersection. Forming a mill during movement grants the same removal privilege. A player may break and reform the same mill on subsequent turns, each time removing an opponent piece. The flying phase activates for a player when they have exactly three pieces remaining. In this phase, that player may move any of their three pieces to any empty intersection on the board, not limited to adjacent points. The opponent, if they have more than three pieces, remains in the movement phase. The game ends when a player has only two pieces left, or when a player has no legal moves available on their turn. The player who cannot move or who is reduced to two pieces loses. No interface controls are standardized, as the game is played on a physical board with tokens. Digital implementations typically use a mouse or touch input to select and place or move pieces.