The clue: It's the size of 10 refrigerators, has access to the equivalent of 200 million pages of information and knows how to answer in the form of a question.
The correct response: "What is the computer IBM developed to become a 'Jeopardy!' whiz?"
Watson, which IBM calls a profound advance in artificial intelligence, edged out game-show champions Ken Jennings and Brad Rutter on Thursday in its first public test, a short practice round ahead of a million-dollar tournament that will be televised next month.
After losing, the human contestants made jokes about the "Terminator" movies and robots from the future. Indeed, four questions into the round you had to wonder if the rise of the machines was already upon us -- in a trivial sense at least.
Watson tore through a category about female archaeologists, repeatedly activating a mechanical button before either Jennings or Rutter could buzz in, then nailing the questions: "What is Jericho?" "What is Crete?"
Its gentle male voice even scored a laugh when it said, "Let's finish 'Chicks Dig Me.' "
Jennings, who won a record 74 consecutive "Jeopardy!" games in 2004-05, then salvaged the category, winning $1,000 by identifying the prehistoric human skeleton Dorothy Garrod found in Israel: "What is Neanderthal?"
He and Rutter, who set a record in winning nearly $3.3 million in prize money, had more success on questions about children's books and the initials "M.C.," though Watson knew about "Harold and the Purple Crayon" and that it was Maurice Chevalier who sang "Thank Heaven for Little Girls" in the film "Gigi." The computer pulled in $4,400 in the practice round, compared with $3,400 for Jennings and $1,200 for Rutter.
Watson is powered by 10 racks of IBM servers running the Linux operating system. It's not connected to the Internet but has digested encyclopedias, dictionaries, books, news, movie scripts and more.
The system is the result of four years of work by IBM researchers around the globe. Although it was designed to compete on "Jeopardy!" the technology has applications well beyond the game, said John Kelly III, IBM director of research. He said the technology could help doctors sift through massive amounts of information to draw conclusions for patient care and could aid professionals in a wide array of other fields.
Watson, named for IBM founder Thomas J. Watson, is reminiscent of IBM's famous Deep Blue computer, which defeated chess champion Garry Kasparov in 1997. But while chess is well-defined and mathematical, "Jeopardy!" presents a more open-ended challenge involving troves of information and human language complexities.