Computer bridge programs are steadily improving. Most of them use simulations, which help plan ahead in the bidding and play. The seventh annual World Computer Championship was played in Menton, France, at the end of June, and the winner, for the third straight year, was the Dutch program Jack, now clearly established as the world's best. It is the brainchild of Hans Kuijf, with Wim Heemskerk and Martin Pattenier as collaborators.

Nine programs were in a preliminary round-robin, which was won by Wbridge5 from France. The French entry seemed headed for a further victory when it was 39 imps ahead with six semifinal deals remaining. But Bridge Baron, an American program that won in 1997, surged ahead and snatched a 4-imp victory. Jack won the other semifinal by 86 against a Japanese entry, Micro Bridge. Jack went on to win the final against Bridge Baron by 71.

Jack bids aggressively and showed it on the diagramed deal from the semifinal round.

Two  copies of the program bid independently, of course, as partners. After an opening of one diamond by the Southern Jack, West overcalled with one heart. The double by the Northern Jack was negative, denying spades. This is a sensible alternative to the American style, in which the double promises exactly four spades.

After South showed spades, North bid two hearts. This cue-bid suggested game and asked for a heart stopper. The jump to three no-trump by South was pushy, but North would have raised two no-trump to three.

West led a heart, and South made the right move by winning the first trick with the ace. An inexperienced player might duck, but it was virtually certain that East held queen-jack doubleton and that the suit would block. West's fourth-best lead indicated that he, or it, held three cards higher than the four, and he, or it, would not have led low from king-queen-10.

The vulnerable overcall marked West with nearly all the missing high cards, so South finessed the diamond jack successfully. The next move was to cash the diamond king, with a low spade to follow. East played low, and the finesse of the 10 drove out the king. Since the hearts were blocked, the contract was safe and 10 tricks were assured. An unimportant 11th developed after slight misdefense.

In the replay, the opposing North-South rested in two diamonds and made just eight tricks. Jack gained 9 imps en route to victory. Next month Jack will play in a tournament with human opponents. How will it fare? We shall see.