AlphaGo was the first machine to win a game of Go against a professional player in a formal match.
Developed by Google DeepMind, AlphaGo defeated European champion Fan Hui 5–0 in a five-game match in October 2015. The result was notable because Go has an enormous number of possible positions, making traditional brute-force search much less effective than in chess.
AlphaGo combined deep neural networks with tree-search methods. It learned from human games and then improved through self-play. In 2016, it defeated South Korean professional Lee Sedol 4–1 in a widely watched match.
Deep Blue is a different system that defeated chess champion Garry Kasparov in 1997. AlphaZero came later and learned several board games through self-play. Those names are related to artificial intelligence, but AlphaGo was the system associated with the historic professional Go victories.