Just Months Old, a Game-Playing A.I. Takes on the World

Competition between humans and artificial intelligence (A.I.) usually plays out in research papers. Occasionally, there's a public performance of a game of chess or Go in front of a staid crowd. Last month in Vancouver, British Columbia, however, I saw something entirely different. The Canadian city was playing host to The International, an annual tournament for the video game Dota 2 boasting a $25 million prize pool -- the largest in esports history. The event was raucous, tribal.