A strong amateur Go player has beat a highly-ranked AI system after exploiting a weakness discovered by a second computer, The Financial Times has reported. By exploiting the flaw, American player Kellin Pelrine defeated the KataGo system decisively, winning 14 of 15 games without further computer help. It's a rare Go win for humans since AlphaGo's milestone 2016 victory that helped pave the way for the current AI craze. It also shows that even the most advanced AI systems can have glaring blind spots.