Dong Kim is one of four pros playing AI program Libratus
The last time poker players squared off against artificial intelligence in 2015, humans were able to prevail over the machine. Four poker pros took on AI bot ‘Claudico’ for 80,000 hands of heads-up No Limit Hold’em action. The battle saw $170 million wagered and the human team winning over $730,000 (in theoretical test money, that is).

Like any good cyborg tale, this story is getting a sequel. Jason Les, Dong Kim, Daniel McAuley and Jimmy Chou are headed back to Pittsburgh to take on the latest iteration of the bot, ‘Libratus’, at the Rivers Casino.

Though the quartet of pros “beat” the bot last time around, the difference was not considered statistically significant to the Carnegie-Mellon research team. Nonetheless, the team took the results of the matches and tried to make adjustments accordingly.

The Claudico group included Les, Kim, WSOP bracelet winner Doug Polk, and Bjorn Li. After the sessions ended, the researchers completely rewrote the logarithm for their AI using feedback from the pros about tendencies and bluffing patterns they observed.

Though bots have been able to defeat chess prodigies, Jeopardy! contestants, and board game players, poker continues to be a problem area for AI. In the last battle, the bots would often make very transparent bluffs, which Les and his fellow players exploited to their advantage.

“Since the earliest days of AI research, beating top human players has been a powerful measure of progress in the field,” Carnegie-Mellon Prof. Tuomas Sandholm said. “Poker poses a far more difficult challenge than these games, as it requires a machine to make extremely complicated decisions based on incomplete information while contending with bluffs, slow play and other ploys.”

The 20-day experiment will run daily at Rivers Casino from 11 am to 7 pm starting on January 11. The total number of hands played will increase to 120,000. The players will play the heads-up matches on a laptop computer, so elements like live tells will not come into play. They will also play two tables at once in order to meet the requisite number of hands.

If the four pros can beat the bot again, they will earn $200,000 to split amongst themselves. Kim and Les are the veterans. Newbie Jimmy Chou is best known for his win in the 2015 Asia Cup of Poker Main Event in Macau. Daniel McAuley is primarily an online cash game heads-up specialist playing as ‘dougiedan678‘, but he also has over $300,000 in online tournament earnings

Humans have fared well historically in these poker battles. In addition to besting Claudico, the live pros also beat Polaris, a Limit Hold’em bot, back in 2007. Polaris challenged pros Phil Laak and Ali Eslami on the first day of play, but the duo made adjustments for the second round of sessions to end the battle on top.