Shin Jin-seo, the world's top-ranked Go player, on Tuesday completed a dramatic comeback against the world’s premier artificial intelligence Go engine, Kata Go, claiming a historic human victory over AI.

Shin, who holds the game's highest achievable rank of nine-dan, dealt Kata Go a decisive 11.5-point defeat playing black in 221 moves in the series finale, which took three hours and five minutes. The 26-year-old South Korean grandmaster became the first human to win an official series against a state-of-the-art Go engine under a two-stone handicap, a margin considered the absolute boundary for human competition against modern AI.

“I believe this series holds immense significance because it clearly demonstrated that humans can still hold their own against AI,” Shin told reporters after the match. “Early on, I simply copied AI moves, which led to heavy fighting and frequent, easy losses. This series taught me that rather than trying to imitate AI, it is far more important to build the board according to my own style.”

In the three-game series, Shin suffered a resounding defeat to Kata Go in the opening match on July 17, but rebounded to beat the Go engine in the second game on Sunday. Shin won 250 million won ($170,000) in match fees and prize money, along with a Genesis G90, Hyundai Motor Co.’s luxury sedan, as a performance award. Reflecting on the 2016 AlphaGo match, Shin noted that taking even a single game against AI at the time felt like a monumental feat.