Cato is played with a standard 32-card pack. In each hand players are dealt five cards and one is turned up to determine trump. After the deal players alternate deciding whether or not to bid (meaning they undertake to take 31 card points) or exchange. Of both players agree to exchange they each discard some cards and draw replacements. This continues until someone bids, or in the revised version published on the web, when the deck runs out the hand is played misère. Play is standard trick-taking with players being obliged to win the trick if possible. A game ends when someone has 121 points and match-play points are scored based on the degree of victory.