How did "AlphaGo" defeat human champions?

AlphaGo defeated human champions through a combination of advanced machine learning techniques and innovative gameplay strategies. The AI system utilized deep neural networks and reinforcement learning, allowing it to learn from vast amounts of gameplay data and improve over time. Initially, it was trained by playing numerous games against human opponents, after which it played against different versions of itself, continuously refining its algorithms based on successful moves and winning percentages^[3].

One significant factor in its victories was AlphaGo's ability to work with an enormous number of potential board configurations—far surpassing human capabilities. Go is considered a significantly more complex game than chess, with an estimated 10 to the power of 170 possible board positions, requiring an AI like AlphaGo to assess an immense search space quickly^[3][4].

During its matches against the world champion Lee Sedol, AlphaGo showcased unexpected and highly creative moves that disrupted conventional strategies. For example, in one match, AlphaGo executed a 'shoulder hit' move that had never been seen in professional play, displaying a level of cunning that surprised even seasoned players^[2][3]. In contrast, Lee Sedol, despite being a top player, struggled to adapt to AlphaGo's aggressive and unconventional playing style, leading to his defeat in several games^[5].

However, Lee managed to win one game in the series by employing a clever move known as the 'Hand of God,' exploiting AlphaGo's mistake during a critical phase of the game. This victory highlighted that while AlphaGo was incredibly powerful, it still had vulnerabilities that could be exploited by skilled human players. Nonetheless, AlphaGo's overall performance established it as one of the strongest Go players in history, defeating Lee Sedol 4-1 in their five-game match series^[1][3].