Book Review: One Jump Ahead: challenging human supremacy in checkers, by Jonathan Schaeffer  

 

Leap of Faith
Man vs. Machine on the Checkered Battlefield

by Chris Lydgate

August 16, 1992, was a fateful day in the history of artificial intelligence: It marked the first time a computer program had ever challenged a human being for a world championship.

The challenger was a 400-pound slab of silicon named Chinook.

The defending champion was a 65-year-old college professor named Dr. Marion Tinsley.

The game was checkers.

In recent years, the ancient art of checkers has gained a reputation as the Rodney Dangerfield of board games. Yet beneath its surface simplicity lies a fierce struggle every bit as challenging as more intellectually respectable pursuits such as chess. The game's deceptive charm--plus the fact that other researchers had largely overlooked it--persuaded Jonathan Schaeffer, a computer science professor at the University of Alberta, to abandon his fledgling chess program and turn to checkers instead. One Jump Ahead is his fascinating account of the project, which began as a mere academic exercise but became an obsession to win the world championship--and, more specifically, to defeat Tinsley.

Tinsley is such an intriguing character he merits a biography of his own. The son of a Kentucky sheriff, he earned a mathematics degree and became a professor at Florida State University in Tallahassee. Following a religious experience, he moved across town to teach at Florida A&M, a primarily black college, and spent his summers canvassing door-to-door to win souls to his Baptist faith.

But beneath this gracious Southern exterior lurked a colossus of the checkerboard. Since clinching the world championship in 1952, Tinsley won every tournament he ever entered and every match he ever played. He retired from checkers several times, only to return to the game stronger than ever. Incredibly, during his 40-year reign, he lost only five games. In Schaeffer's words, Tinsley was "as close to perfection as humanly possible."

Tinsley was up against a formidable opponent, however: Chinook boasted eight brains, a database of 85 billion endgame positions and the ability to peer as many as 27 moves into the future. A single keystroke could transform its personality from cautious to swashbuckling, making it a difficult player to prepare against.

To non-combatants, Chinook may have seemed like a boardgame Terminator, an indestructible automaton. But as Schaeffer's book shows, its development was surprisingly haphazard. In fact, Chinook was plagued by bugs: Its vaunted databases were riddled with holes; its knowledge of checkers was surprisingly unsophisticated, at times almost laughably naive; and when Schaeffer made last-minute corrections to the program, he often accidentally introduced new errors. Far from being an infallible juggernaut, Chinook comes across as a digital enfant terrible, capable of sparkling brilliance and maddening blunders in the same game.

Held in London, the clash of the checkerboard titans generated intense media coverage and was portrayed as a battle between man and machine. Tinsley even cast the match in spiritual terms: "I have a better programmer than Chinook," he told the Daily Telegraph. "God gave me a logical mind." In the end, Tinsley vanquished Chinook, thanks to flashes of brilliance and a mysterious computer malfunction.

Schaeffer learned from his mistakes and challenged Tinsley to a rematch in 1994. But the return bout was a puzzling anti-climax: After six drawn games, Tinsley complained of an upset stomach, withdrew from the match and forfeited the title. A few days later, doctors discovered a malignant tumor in his pancreas. Tinsley died the next year, leaving the cancer-proof computer as the world's reigning champ.

One Jump Ahead is not only gripping, it also raises many provocative questions. Could Tinsley have beaten Chinook in the rematch? Are computer programs destined to outplay humans in chess, go, bridge, and even poker? Perhaps most important, what does Chinook's triumph imply for the future of machine--and human--intelligence? After all, Chinook's strength lay in its gigantic databases, which effectively reduced the game's creative subtleties to a mechanical exercise in searching a catalog.

But Schaeffer makes a persuasive case that we should not define computer intelligence by its similarity to the human brain. Rather, he says, we should look at the results: Can a robotic program excel at a task which, in humans, obviously requires imagination and intelligence? The answer, at least in the case of Chinook, is a resounding yes--and the implications must be correspondingly profound.

[First published in Willamette Week, April 5, 2000]