Lee told the news agency that his victory in 2016 was likely down to a bug in Google’s code, after he used a move that could not be “countered straightforwardly” and the program responded in an unusual way that gave him an opening and eventually forced AlphaGo to surrender.
Software programs long ago became adept at classic board games like backgammon. Their rapid progress culminated in the historic victory of IBM’s Deep Blue computer over world chess champion Gary Kasparov in 1997.
In Go — which dates back to ancient China — two players alternate placing white and black stones on a grid. The goal is to claim the most territory. To do so, players surround their opponent’s pieces so that they are removed from the board.
Using deep-learning artificial intelligence however, programs such as AlphaGo have been able to build up their mastery over the years and draw on data from thousands of games.
The 36-year-old Lee, who won 18 international competitions and 32 domestic tournaments, according to Yonhap, resigned from the Korea Baduk Association (KBA) this month, ending a 24-year career. Baduk is the Korean name for Go.
While Lee is no longer playing professionally, he is helping to develop just the type of AI that pushed him out of competition. Next month, he has a match against HanDol, a South Korean AI program which has already defeated the country’s top five Go players. Lee will also start with the edge in the first match.
“Even with a two-stone advantage, I feel like I will lose the first game to HanDol,” he said. “These days, I don’t follow Go news. I wanted to play comfortably against HanDol as I have already retired, though I will do my best.”
CNN’s Matt McFarland and Sophia Yan contributed reporting.