Duplication is played with 49 stones with a white and black side, on a board consisting of 7x7 squares. The game starts with 2 stones for each player, crossed and in each corner of the board. The goal of Duplication is to get more stones than the opponent on the board.
Taking turns, the players move one of their stones on the board 1 or 2 squares in a chosen direction (horizontally, vertically or diagonally) to an empty square. When the stone is moved 1 square, it is duplicated and a new stone comes into play. When the stone is moved 2 squares, no new stone appears. Then all the opponent's stones adjacent to the moved stone are turned over to the current player's color.
The game ends when one of the players is unable to make a move. The player with the most stones on the board wins the game.