AS FRIDAY NIGHT became Saturday morning, Dong Kim sounded defeated.
Kim is a high-stakes poker player who specializes in no-limit Texas Hold ‘Em. The 28-year-old Korean-American typically matches wits with other top players on high-stakes internet sites or at the big Las Vegas casinos. But this month, he’s in Pittsburgh, playing poker against an artificially intelligent machine designed by two computer scientists at Carnegie Mellon. No computer has ever beaten the top players at no-limit Texas Hold ‘Em, a particularly complex game of cards that serves as the main event at the World Series of Poker. Nearly two years ago, Kim was among the players who defeated an earlier incarnation of the AI at the same casino. But this time is different. Late Friday night, just ten days into this twenty-day contest, Kim told me that he and his fellow humans have no real chance of winning.
“I didn’t realize how good it was until today. I felt like I was playing against someone who was cheating, like it could see my cards,” he said after returning to his hotel room to prep for the next day. “I’m not accusing it of cheating. It was just that good.”
The machine is called Libratus—a Latin word meaning balanced—and Kim says the name is an apt description of the machine’s play. “It does a little bit of everything,” he says. It doesn’t always play the same type of hand in the same way. It may bluff with a bad hand or not. It may bet high with a good hand—or not. That means Kim has trouble finding holes in its game. And if he does find a hole, it disappears the next day.