A computer program ended its five-game match against the world's top-ranked Go player with another win Tuesday, sealing a landmark achievement for artificial intelligence.
The intricate game of skill had long stumped computers. The match was "the most mind-blowing game experience we've had so far," Demis Hassabis, cofounder of Google DeepMind, the makers of the AlphaGo program, said at a postgame news conference.
Tuesday's contest was the closest of the five games played over the past week, the only one decided by counting points, rather than ending in resignation by AlphaGo or opponent Go grandmaster Lee Sedol.
In Tuesday's game, AlphaGo made an early error, which Lee attempted to capitalize on, but ultimately the Google program fought back and gained control.
Immediately after the game, Lee looked sad and exhausted, wiping tears from his eyes before leaving his seat for the final time. He was apologetic after the game, saying, "I regret that I wasn't able to achieve a winning result today."