There are 28 dominoes on the board. Each domino has a pair. These pairs add up to 12 (the number of dots on each dominoes). You must select 2 bones dominoes. If the selected dominoes add up to 12, then these dominoes are removed from the field. Then closed dominoes are opened only if there are no tiles above or below. You must remove all the dominoes, good luck! If the game ends on 10/2, 11/1 or 12/0 then you get special victory statuses.