Concentration is played by two players (human and/or computer). The game starts with all 52 Karten in the deck being placed face down on the play area. Player One begins the game by flipping any two Karten in the play area. If the two flipped Karten match, then those two Karten are removed from the play area and the player gains two points and another turn. If the two flipped Karten do not match, then the two Karten are returned to their original face down positions and it becomes the other player's turn. Once all the Karten have been matched the game ends. The player who has the most matches (points) at the end of the game wins.