The 1997 world champion of computer bridge uses AI planning techniques to plan its declarer play.

Accomplishment

Bridge Baron is a computer program that plays bridge. It won the 1997 world championship of computer bridge, the Baron Barclay World Bridge Computer Challenge, as reported in The New York Times and The Washington Post. The five-day competition, which was hosted by the American Contract Bridge League in July 1997, included five computer programs, from the US, Japan, and Germany. The Bridge Baron won every head-to-head match that it played against the other programs.

Copies of Bridge Baron are available from Great Game Products of Bethesda, MD.

AI Planning in Bridge Baron We developed an AI planning algorithm for generating and evaluating strategies for declarer play in the game of bridge. As shown in the figure, the algorithm generates alternative strategies for how to play the game, and evaluates these strategies to determine which of them is best. We incorporated our implementation of this algorithm into Bridge Baron, an existing commercial product owned by Great Game Products. This helped Bridge Baron win the 1997 championship, and it has been used in all subsequent commercial releases of Bridge Baron. The planning algorithm is a special case of a technique called ordered task decomposition that can be used in a wide variety of planning problems. For example, the SHOP2 planning system, a domain-independent planner using ordered task decomposition, won a prize at the AIPS-2002 International Planning Competition.

Publications

By us:

• Stephen J. Smith and D. S. Nau. A planning approach to declarer play in bridge. Computational Intelligence, Feb. 1996. An earlier version is available here.
• Stephen J. Smith, D. Nau, and T. Throop. Total-order multi-agent task-network planning for contract bridge. In AAAI-96, August 1996. An earlier version is available here.
• Stephen J. Smith, Dana Nau, and Thomas Throop. AI planning's strong suit. IEEE Expert, December 1996.
• Stephen J. Smith, Dana Nau, and Thomas Throop. Success in Spades: Using AI Planning Techniques to Win the World Championship of Computer Bridge. AI Magazine, June 1998. An earlier version is available here.

By others:

• G. Walker. Beaten in spades. New Scientist, Nov. 16, 1996.
• A. Truscott. Bridge: Bridge software is improving and already beats humans in one respect: it never blames partner. The New York Times, Aug. 16, 1997, p. A19.
• R. Chandrasekaran. Program for a better bridge game. The Washington Post, Sept. 15, 1997, Washington Business section, pp. 1,15,19. An electronic copy is available here.
• ERC Work Includes a Game, but That's Not All. National Science Foundation, 1997.

Authors

The AI planning techniques used in Bridge Baron were developed by Stephen Smith, Dana Nau, and Tom Throop. Here is how to contact us:

Stephen J. J. Smith and Tom Throop Great Game Products, Inc. 7825 Tuckerman Lane, Suite 206 Potomac, MD 20854 Tel: 800-426-3748 or 301-299-9005 Fax: 301-765-8004 http://www.bridgebaron.com

Dana S. Nau Department of Computer Science and Institute for Systems Research University of Maryland College Park, MD 20742 Tel: (301) 405-2684 http://www.cs.umd.edu/~nau