THE 10^th ANNUAL WORLD COMPUTER-BRIDGE CHAMPIONSHIP

Verona, Italy

July 17-21, 2006

Alvin Levy[1]

The 10th annual World Computer-Bridge Championship, sponsored by the American Contract Bridge League (ACBL) and the World Bridge Federation (WBF), was held in Verona, Italy alongside the WBF’s 12th World Bridge Championship.  Seven bridge-playing software programs, or robots, competed for the 2006 computer-bridge world champion title.

History

The ACBL inaugurated an annual computer-bridge championship in 1997 as a way of encouraging computer-bridge software developers to accelerate their robots’ development to expert class, with the hopeful result of more software development for educational purposes and generally promote bridge.  The WBF supports this event and starting in 1999 it became an ACBL/WBF joint venture.  Since its inception in 1997, the championship has been held every year at an important human international bridge event.  The first ten championships have been held three times at ACBL North American Bridge Championships, six times at WBF World Championships and once at the European Bridge League’s (EBL) first European Open Championship.  For a complete history and details of previous championships go to ny-bridge.com/allevy/computerbridge or computerbridge.com.

Technical remarks

A bridge “table” consists of a central server, or Table Manager (TM), and four connecting computers that “seat” the robots.  The TM distributes the four hands of each board to the robots.  Play proceeds automatically, with pauses for explanations of “alertable” bids.  The TM receives and passes information from and to the robots and records the play.  This year P4 3 GHz/512 MB PCs were used, running under Windows XP.  The speed of play was set at two minutes per pair per deal, approximately half that of human play.

Contestants submit a Convention Card (CC) with their bidding and carding understandings one month before the competition.  Since this information is stored in the opponent robots’ memories before play begins, few explanations (alerts) are necessary during play.  In the instances where the CoC requires explanations, the pertinent information is manually input into memory and play continues.

Without getting into the details, most of the robots are programmed with a combination of knowledge-based AI (sets of rules) and search-based AI (simulations).

Play format

The competition is in the form of team matches, with a team’s four identical robots sitting North and South at one table and East and West at the other table.

This five-day event starts with a 28-board round-robin.  The top four robots advance to the semifinal knockout stage, consisting of a 64-board semifinal with carryover.  The round-robin is scored on an international 30-VP scale.  To earn a carryover in a KO match, a robot must win its head-to-head round-robin match against its KO opponent and end higher in the overall round-robin standings.  The carryover is the lesser of the two VP differences.

The competitors

Seven robot teams entered this year’s championship.  The competitors include newcomer Bridge Shark (Denmark), four-time champion Jack (The Netherlands), defending champion Wbridge5 (France), the 1997 champion and 2003 and 2004 runner-up Bridge Baron (USA), the 2001 runner-up Micro Bridge (Japan), three-time runner-up, Q-Plus Bridge and Blue Chip Bridge (U.K.).

The robots and their developers are shown in Table 1, along with their VP round-robin totals.

Table 1.  Robots, developers and round-robin standing

Results

The round-robin ended with Jack topping all competitors with 124 VPs.  Second through fourth were within five VPs of each other.  Micro Bridge, 20 VPs behind Jack at 104 VPs, finished second, WBridge5, with 102 VPs was third and Q-Plus Bridge with 99 VPs was fourth.

Table 2 shows the IMP/VP results of each round-robin match.

Table 2.  Round-robin match results

The semi-final saw Jack, with a 16 IMP carryover, defeat Q-Plus Bridge, 239-41, and Micro Bridge defeat WBridge5 141-133.  In the final, Jack, with an 8 IMP carryover, defeated Micro Bridge 217-54.  Jack appears to be the class of the field, winning all its round-robin matches and convincingly winning its semi-final and final matches.

The Play

Some of the boards played in the sixth and seventh round-robin matches were earlier played simultaneously in the Rosenblum (Open team championship) round of 32 and McConnell (Women's team championship) round of 16.  Two boards from these matches follow.  In the round robin of the computer championship each hand was played 6 times, while in the Rosenblum round of 32 each hand was played 32 times and in the McConnell round of 16 each hand was played 16 times.

An interesting hand as 6¨ and 6© makes on any lead, but not 6ª on a club lead.  In the McConnell none of the 16 pairs reached either cold slam, while 3 reached 6ª, making once.  In the Rosenblum 6© was reached 7 times, 6¨ once, and 6ª reached 6 times, making twice.

In the computer championship, 6© was reached twice with no pair in 6ª.

Micro Bridge reached 6© after Micro Bridge North showed extras and fitting cards with its 4¨ bid.  Q-Plus Bridge found 6© when it assumed club high cards with East and making sure it had four of the five keycards and the trump queen.

The robots did better than the humans, reaching the correct slam 1/3 of the time and the wrong slam never, compared to the expert humans who reached the correct slams 1/6 of the time and the wrong slam 1/4 of the time.

In the Rosenblum teams, 4© was reached 25 times and made 11 times.  In the McConnell 4© was reached 11 times and made 4 times.  In the computer championship 4© was bid 5 times and made twice.  In the Jack versus WBridge5 round robin match, both reached and made 4©.

When WBridge5 was declarer the play went:

ªQ to the ªA; §K to the §A; ªK ruffed; §Q discarding a diamond; §J discarding a diamond; §8 ruffed as West discarded a diamond; ¨Q to the ¨A; ¨2 ruffed; spade ruffed as East discarded a diamond; ¨10 ruffed and over-ruffed with the ©J; club ruffed and over-ruffed by West with the ©10; South make the ©A and ©Q.

When Jack was declarer the play went:

ªQ to the ªA; spade ruff; club to the §K and §A; trump return ducked to West’s 10; ©K returned to South’s©A;  club ruff; diamond finesse losing to K; declarer claiming the rest.

Jack won the final against Micro Bridge convincingly.  Here is one board from that match.

Micro Bridge was +170 in 1ª and down 2 for –500 in 2¨x.  8 IMPs for Jack.

Hans Kuijf, developer of Jack, explained Jack’s bidding at both tables.  Jack follows some strict rules for balancing when an opening one heart or one spade is passed around to it.  With four trumps and a singleton in the other major, it needs at least 12 HCP to reopen, so it passed.  At the other table, Micro Bridge balanced with two diamonds.  After two passes, West balanced with a takeout double that promised a maximum pass with length in the unbid suits and spade tolerance.  East converted to penalties.

General remarks

Every year the level of play of the top robots improves.  This year is no exception, with more consistent good declarer play, defense and bidding, especially by the apparent leading robot, Jack.  On many hands the top robots’ play is expert, but while consistency is improving the top robots are not yet near overall expert class.

For more information on this year’s championship, past championships, published articles, photos and the robots’ websites, go to computerbridge.com or ny-bridge.com/allevy/computerbridge.