GIB's spectacular achievements as declarer are based on a fast-as-lightning 'double dummy solver', a piece of software which can determine the optimal contract and line of play for each deal, as well as the best defense. This double dummy solver was also put into action in the bidding. The bidding relies on a very extensive data base of bidding rules, but as soon as this data base fails to provide an answer for the next call to be made, GIB rapidly generates deals which are consistent with the auction up to that point. He then determines the optimal contract for all those deals and selects the call which most often leads to the best-scoring contract.
This procedure is reminiscent of these typical rubber bridge auctions in which one of the partners at a given stage says that he has sufficient information and makes the final call. Sometimes, this goes completely wrong, but it has the advantage of usually avoiding the misunderstandings of inexperienced partnerships. Ginsberg presented his computers, GIB East and GIB West (let's call them E.Gib and W.Gib - the bridge BeeGees, one could say. Ed.) with a bidding quiz developed by Larry Cohen, based on the deals and scores of the 1997 Politiken World Pairs.
 
 

3. E/NS	datum score:NS -320			WEST    W. Gib    -       1       4	NORTH  -  -  2  Pass	EAST  E. Gib  1  3  Pass	SOUTH  -  1  Pass  Pass
A 8 6 4 3 2  10  Q 9  10 7 6 3		K J 9 5  Q 7 5 3  K 8 5  A 5
-	-

5. W/NS	datum score:NS -870			WEST    W. Gib    1NT     2      3     Pass	--------	EAST  E. Gib  2   3  6	------
Q 4  A 8 6 3  A Q 4 3  K Q 9		7  K Q 10 9 7 5 2  10  A 10 5 3
-	-

On the second deal, the auction goes according to the data base rules up to 3. The 2-bid promises four-card heart support and a doubleton in spades. Then, E. Gib is left once more to his own devices, and after analysing several dozen possible west hands it concludes that the odds favor a slam, and so he bids it. Again an 11-imp gain. Over the twenty deals of the quiz, the Gibs net +2 - an excellent result considering that the scoring is based on that of a field of world class players.

And so, Ginsberg considered himself ready for the match against Zia and his regular partner, Michael Rosenberg. The match was played last month [August '98] on Internet's OKBridge; fourteen deals with Butler scoring against the OKBridge field. After thirteen of the fourteen deals Zia-Rosenberg were leading 24-16, in part thanks to a successful 1-psych by Zia: the Gibs kept bidding to a way-too-high 3NT, and had to suffer in silence as Zia and Rosenberg garnered the first six tricks in spades.

The Gibs had an opportunity to decide the outcome in their favor on the very last deal:
 

E/NS	K 10 6 3  A 4 2  10 8 3  A Q 3			WEST    W. Gib    -    Pass    Pass    Pass	NORTH  Rosenberg  -  2  3  Pass	EAST  E. Gib  1  Double  Pass  Pass	SOUTH  Zia  1  2  4
J 9 7 4 2  Q 8  9 7  9 6 4 2		A 8 5  5  A K Q J 5  K 10 8 7
-	Q  K J 10 9 7 6 3  6 4 2  J 5

In the previous issue of IMP we predicted a GIB world title in the Par Contest at the Lille Olympiad. GIB got a foretaste with an overwhelming victory in the world championship for bridge programs at the Chicago Summer Nationals. In the semi-finals, GIB faced Bridge Baron:
 

S/neither	K Q10 7 6  K 9 7 6 3  -  J 8 3			WEST    W. Gib    -    Pass	NORTH  N. Baron  -  Pass	EAST  E. Gib  -  Pass	SOUTH  S. Baron  2
J 9 8 5 2  Q 2  K 9 3  A K 7		A 3  J 10 4  8 6 4 2  Q 9 6 4
-	4  A 8 5  A Q J 10 7 5  10 5 2

Against South's 2 (weak two), W.Gib led the Q, won by South's ace. Next came a spade to the queen and ace, and E. Gib persisted with the J for dummy's king. Baron now pitched a club loser on the K. Besides the A, the defense is entitled to one trick in hearts, two in clubs and the K. The setting trick will have to come from the trump suit. The Gibs finish the job in elegant fashion: West wins the club lead from dummy with the king and underleads his A. East wins with the queen and cashes

Next month: the World Championship Par Contest.