9 Men Morris

Nine Men's Morris is a strategy board game for two players that emerged from the Roman Empire.
The game has also been called Cowboy Checkers and is sometimes printed on the back of checkerboards.
Nine Men's Morris is a solved game in which either player can force the game into a draw.

The board consists of a grid with twenty-four intersections or points. Each player has nine pieces, or "men", usually coloured black and white. Players try to form 'mills'— three of their own men lined horizontally or vertically—allowing a player to remove an opponent's man from the game. A player wins by reducing the opponent to two pieces (where he could no longer form mills and thus be unable to win), or by leaving him without a legal move.

The game proceeds in three phases:

Placing men on vacant points
Moving men to adjacent points