Players can agree to shorter rounds. Traditional rules say if you have a double-12 domino set you'd play all 13 rounds (including the “zero” round). But you can also agree to play best of three or five rounds. Just choose an odd number to ensure someone is a winner. The winner is always determined by whoever has the lowest pip count after all agreed-upon rounds. Some house rules always set the max at three rounds. This is how our Mexican Train Dominoes apps and free online Mexican Train games*** work. It helps speed up the game for more casual play.