THE 14^th ANNUAL WORLD COMPUTER-BRIDGE CHAMPIONSHIP

Philadelphia, PA, USA

October 10-16, 2010

by Alvin Levy[1]

The 14^th annual World Computer-Bridge Championship (WCBC), hosted by the American Contract Bridge League (ACBL) and the World Bridge Federation (WBF), was held in Philadelphia, PA, USA, alongside the WBF’s World Bridge Series Championship.  Since its inception in 1997, the WCBC has been held annually alongside an important ‘human’ bridge championship.  Next year’s event will be held October 23-28, 2011, in The Netherlands, alongside the WBF’s 40^th World Team Championships.  For the complete history and details of previous championships, as well as many articles on robot play, go to www.computerbridge.com

Technical remarks

A bridge ‘table’ consists of a Bridge Monitor (BM) that manages the game, and four connecting computers that seat the robots.  The BM manages and records the play.  Play proceeds automatically, with pauses for occasional manual exchanges of information when explanations of bids are necessary.  All the robots use identical computers.  This year dual Intel Xeon processors 3.6GHz/2GB Ram desktops (HP Workstation xw6200) were used, running under Windows XP Pro.  The timing of play was set at two minutes per pair per deal.

The format is team play, with each team consisting of four identical robots.  The event starts with a 32-board round-robin scored on the International 30-Victory Point (VP) scale (0-3 IMPs is 15-15 VPs; 4-10 IMPs is 16-14 VPs; up through 101+ IMPs is 25-0 VPs). The top four robot teams advance, with carryover, to the 64-board semifinal KO stage.

Competitors and round-robin results

Seven developers entered their bots in the six-day event.  Going into the seventh and last round, any of five entries could have finished from first to fifth.  The final standings were: WBridge5 (developer Yves Costel, France) topped the field with 110 VPs; Shark Bridge (John Norris, Denmark) was close behind with 108 VPs; Jack (Hans Kuijf, The Netherlands) followed with 106 VPs; Bridge Baron (Stephen Smith, USA) rounded out the top four with 103 VPs; Q-Plus Bridge (Hans Leber, Germany) losing its last match to Shark Bridge by a 24-6 VP margin, was eliminated with 99 VPs; Micro Bridge (Tomio and Yumiko Uchida, Japan) finished with 74 VPs; and newcomer Moose Bridge managed only 6 VPs.

A deal (hands rotated) from the first round robin match raised an interesting question: What to do with a weak 4-4-3-2 hand when partner opens a strong 1NT?

A pass was the most popular choice, and, at four tables, the final contract was 1NT, with eight tricks available under normal play. At two tables, West bid 2♣ hoping to find a four-card major. This worked well for Q-Plus Bridge against Moose Bridge, as Q-Plus Bridge was allowed to play in 2♥, making four for a 2-IMP pickup.

For Jack, against Bridge Baron, the tables were turned when North made a balancing double over 2♥, and South declared 3♣.  Jack did well to limit its loss by defending carefully.

West led the ♥10.  Declarer won the ace, ruffed a heart, crossed to the ♠A and ruffed another heart. Declarer then led to the ♠K and ruffed a third heart. With six tricks in hand, the ♠Q was led

and East ruffed with the ♣Q rather than the ♣7, thus avoiding an endplay that would have allowed declarer to make nine tricks.  The play continued, ♣A, ♣7 to partner’s ♣J and a diamond through the king for down one.  Robots use a simulation technique in the play whereby the unseen cards are distributed randomly in a number of ways, consistent with the bidding and play, and then analyzed to see what play will work most often.  Jack, and the other top robots, will not often miss a best play in an endgame.  Just as in human play, the fewer the cards remaining, the easier it is to get the play right.

Another interesting deal from the third round follows.  In one match, at both tables, an opening lead against a slam swung 14 IMPs.  In another match a strange looking play at trick one was right...but to no avail.

⁽¹⁾ strong; ⁽²⁾ not game force; ⁽³⁾ waiting, denies 3 hearts; ⁽⁴⁾ 2 keycards with heart Q

As he cards lie, only a spade lead allows 6♥ to make.  At table 1 Jack made the unfortunate 'blind' lead of a spade and 6♥ made.  At table 2, Shark Bridge South doubled over 2♥ and had an easy club lead to defeat 6♥ when partner bid 3♣.

A strange play at trick one is right...but to no avail.

A most interesting play occurred in the Q-Plus Bridge vs. Micro Bridge match.  At one table, Micro Bridge opened 4♥ and played it there, making 7 on a spade lead.  At the other table Q-Plus Bridge played in the superior 6♠ contract from the West position. [7♠ is the best contract, as it makes almost always when 6♥ and 6♠ makes.] North led the ♦A and Q-Plus Bridge ruffed with the ♠Q and led the ♠8! A strange looking sequence of plays, but a reasonable plan.  It gives up the overtrick when trumps are 3-2 or if there is a singleton jack, but can win if spades are jack fourth in either hand.  If the player with jack forth wins the jack at trick two, declarer will succeed on many hands (not on this one with a club return because South is void in hearts and declarer can't get to its hand to pull the last trump.), while ruffing with the 8 and leading the ♠Q at trick two never wins against jack fourth.  Shark Bridge South correctly ducked the spade return, guaranteeing defeat, as winning and returning a club might lose if declarer started with ♣AQ. Of course, playing one high spade before returning the ♠8 might pick up the singleton jack, or induce South to more readily win the jack knowing partner has no more trumps.  These possible variations in play depend on the limited hand samples used in the play simulation analysis.

Semifinals

In the semifinal matches, WBridge5 defeated Bridge Baron by a score of 154-123 and Jack easily defeated Shark Bridge, 183-58.

Final

WBridge5 battled Jack for the title, with a carryover of 2 IMPs.

WBridge5 led through most of the match, partially due to aggressive bidding, as demonstrated at both tables in this deal from the third quarter.

WBridge5 gained 11 IMPs, reaching a good vulnerable 5♣ contract at one table and bought the contract with a preemptive 3♠ bid at the other.

With 12 boards to go in the final KO match, WBridge5 was up 45 IMPs. Starting on board 53 Jack made a miraculous comeback.  Jack reached 4♥, while at the other table WBridge5 played in 3NT from the North side and paid the price of 13 IMPs when a club was led and the ♥K was offside.

Jack triumphed over WBridge5, 150-120, to retain the championship it won in 2009.

Congratulations to Hans Kuijf, and his creation, Jack.