9-dan Shin Jin-seo, considered the strongest player in the world, has finally defeated the strongest Go artificial intelligence (AI) in existence, KataGo.

On the 19th, at the Korea Economic TV studio in Jung-gu, Seoul, in Game 2 of the SSEN Math·Hankyung Gisinjeon, Shin Jin-seo defeated KataGo by 4.5 points after a hard-fought battle lasting about 4 hours and 50 minutes.

This game was a handicap match in which Shin Jin-seo took Black with two stones placed on the board at the start. Although it was a two-stone handicap, this is the first time that KataGo, the highest-performing Go AI to date, has been beaten in an official game.

KataGo has shown overwhelming strength in numerous practice games against professional players, winning not only with a two-stone handicap but even when giving three and four stones. For this reason, this victory is regarded as one of the most meaningful achievements by a human professional against the strongest AI currently in existence.

Since 2016, when 9-dan Lee Sedol earned a historic single win in an even five-game match against AlphaGo, Go AI has advanced by leaps and bounds. As KataGo is now regarded as far surpassing AlphaGo of that time, the victory by Shin Jin-seo, even taking into account the handicap, is being received as a new milestone for the global Go community.