DeepMind's AlphaGo won the first game of its five-game match against top Go professional Lee Sedol on March 9, 2016, going on to win the series 4-1. Go had long been considered far harder for computers than chess due to its vast search space, making the victory a landmark for deep reinforcement learning. AlphaGo's move 37 in Game 2 became famous as a creative play no human would have chosen.