Lee Sedol was a professional player from South Korea who has achieved the 9 dan rank in Go, an ancient board game that requires players to use strategic thinking and surround more territory than their opponent. With 18 international championships to his name, Sedol, now retired, is recognized as one of the greatest players in the game.

In 2016, he participated in the Google DeepMind Challenge Match against AlphaGo, an artificial intelligence program developed by Google DeepMind. In the game, Lee's unexpected move at white 78 developed a white wedge…