AlphaGo is an AI system that defeated Lee Sedol in the game of Go in the year ____, utilizing ______ .

AlphaGo is an AI system developed by DeepMind that famously defeated the South Korean Go champion Lee Sedol in the year 2016, utilizing a combination of deep neural networks and reinforcement learning. The system learned from playing millions of games against itself and analyzing numerous historical games played by humans. AlphaGo's architecture included convolutional neural networks that evaluated board positions and predicted the outcomes of moves. This innovative approach allowed AlphaGo to not only understand established strategies but also to explore new and unconventional tactics that human players had not considered. The victory was significant as it highlighted the capabilities of AI in mastering complex games, paving the way for advancements in AI research and its applications in other fields.