Nine Men's Morris is a classic two-player board game.

In the first phase of the game, each player has to place pieces on empty slots. If a player places three pieces in a line, they form a "mill", and they can remove an opponent's piece from the board. The first phase ends when all pieces are placed.

In the second phase, each player can move a piece to an adjacent point, as long as the adjacent point is empty (no jumping). As in the first phase, forming a mill removes one opponent's piece.

The game ends when a player only has two pieces left.