Computer programme AlphaGo won its third game in a row Saturday, ensuring it of victory in the landmark five-game machine-versus-human contest in the board game Go.
The Google software beat South Korean champion Lee Sedol after more than four hours of game play in Seoul, seen as one of the biggest tests of the power of artificial intelligence (AI).
AI systems had long struggled to beat humans at Go, which was previously thought to be too complex for computers, as they lacked the self-learning software needed to adapt to the millions of possible gameplay scenarios.
The rules of Go, which originates in China, are easy in principle: two players try to conquer spaces with white and black stones on the board, which is divided by vertical and horizontal lines into a grid.
AlphaGo was developed by Google's DeepMind AI branch to forecast the most probable moves of its human opponent and adjust itself accordingly.
In October, the programme won a five-game match against Fan Hui, a top European player, ranked well below Lee internationally.