Spades

Four players sit round one table and the two sitting opposite each other are partners. The whole deck is dealt, thirteen cards each, and spades are always trump.

Before a card is played, everyone says how many of the thirteen tricks they expect to take. Every bid is said out loud, so you hear the others as they land, and the two bids on your side add up to what your partnership has to make. A bid of zero is a nil: it pays a hundred if you take no trick at all and costs a hundred if you take one, and your partner's tricks still count towards their own bid.

Play goes round the table. Follow the suit that was led if you hold it, and play anything you like if you do not. A spade beats any other suit, and inside a suit the higher card wins with the ace on top. Nobody may lead a spade until one has already been played on some earlier trick, unless they hold nothing else. Whoever takes a trick leads the next one.

Make your contract and your side scores ten a trick, plus one for each trick over. Miss it and your side loses ten a trick. Those extra tricks pile up as bags, and every tenth bag your side has collected costs you a hundred. The deal moves one seat on after every hand, but against the computer you always bid first and lead the first trick. First side to five hundred wins the match.