International Computer Games Association Journal          September 2004          pp. 189-193

THE 8^th ANNUAL ACBL’S WORLD COMPUTER COMPUTER-BRIDGE CHAMPIONSHIP

New York City, New York, USA

July 13-17, 2004

Alvin Levy[1]

The American Contract Bridge League’s (ACBL) 8th annual World Computer-Bridge Championship was held in New York City in conjunction with the ACBL’s summer North American Bridge Championships (NABC).  Eight of the best bridge-playing software programs, or robots, competed for the title of 2004 computer-bridge world champion.

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.  Since then progress has accelerated and the top robots have advanced significantly to the level of strong club player.

This championship has been held every year at an important human international bridge event, with me as the organizer.  The preceding seven championships were held three times at ACBL NABCs, three times at World Bridge Federation (WBF) World Championships and last year at the European Bridge League’s (EBL) first European Open Championship.  When hosting this championship, the ACBL, WBF and EBL have given both financial and organizational support.  For a complete history and details of previous championships go to ny-bridge.com/allevy/computerbridge.

Technical remarks

A bridge “table” consists of a central server, or Table Manager (TM), and four connecting computers, which “seat” the robots.  The TM distributes the four hands of each board to the robots.  Play proceeds automatically with the TM receiving and passing information to the robots and recording the play.  This year P4 2.4 GHz/512 MB PCs were used, running under Windows XP.  The speed of play was set at 2 minutes per pair per deal, approximately half that of human play.

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

Preparation

This is very much a group effort between the organizer, the computer-bridge software developers and the ACBL.  The Conditions of Contest are set by an administrative committee with input from the software developers and bridge experts.

It is important that the developers understand the opponent robots’ methods in advance of the competition so that they can prepare defenses.  In human play advance notice, with unusual systems not allowed, are not necessary.  However, in computer-bridge play the developers need time to program defenses and store information about the opponent robots’ methods.  Contestants are required to submit a Convention Card (CC) one month before the competition.  This is in the form of a spreadsheet, with over 100 questions.  Once the CCs are published contestants ask each other (through email) even more detailed questions about their methods and conventions.  Since this information is stored in the robots’ memories before the competition begins, few alerts are necessary during play.  In the few instances where alerts are required the pertinent information is input into memory and play continues.

Play format

The competition is in the form of team matches, with a team’s robots seated N-S at one table and E-W at the other table.  A match, or part of a match such as a 16-board set, is played sequentially, first at one table (closed room) and then at the other table.

The five-day event starts with a 24-board round-robin with the top four robots advancing to a 64-board knockout (KO) semifinal with carryover.  The round-robin is scored on an international 30-VP scale, where the winning side receives a maximum of 25 VPs for a 52 or more IMP victory.  To earn a carryover in a KO match, a “team” must both win its head-to-head round-robin match against its KO opponent and end higher in the overall standings.  The carryover is the lesser of these two VP differences.

The competition

The round-robin ended with Bridge Baron topping all competitors with 147 VPs.  The other three teams advancing to the semifinals were Wbridge5, closely behind with 145 VPs, Jack, with 138 VPs and Micro Bridge with 131 VPs.

The robots, their developers and the final round-robin standing are shown in Table 1.  Table 2 shows the IMP/VP results of each round-robin match and the round that each match was played.

Table 1.  Robots, developers and round-robin standing

Table 2.  Round-robin match results

Even though Q-Plus Bridge did not make the semifinals, it demonstrated fine play on this deal.  This hand occurred in the fourth round against Jack.  26 IMPs were at stake; 13 IMPs to Q-Plus Bridge if it makes its 6© contract and 13 IMPs to Jack if it fails.  Note: In every set of boards throughout the championship there were demonstrations of expert play and poor play.  The hands shown in this report demonstrate some of the expert play.

With the spade bid by South, West’s hand became bigger, and the Q-Plus Bridge robots bid to an overly aggressive heart slam.  South led a low spade.  Declarer finessed, drew trumps, eliminated diamonds and spades, cashed the §A and led a low club.  The defense was helpless and Q-Plus Bridge scored +1430.

Semifinals

In the semifinals, round-robin first place finisher, Bridge Baron, had a 14 IMP carryover against fourth place finisher, Micro Bridge, and second place finisher, Wbridge5, had a 2 IMP carryover against third place finisher, Jack.

The last time Jack played Wbridge5 in the championship KO stage was the 2002 finals.  That final was the closest KO final in computer-bridge history with Jack winning by 1 IMP.  This year Jack continued its winning ways, this time defeating Wbridge5 more comfortably, 157-118.  In the other semifinal match Bridge Baron defeated Micro Bridge 166-126.