Artificial intelligence (AI) has beaten a human in the first of five matches of the complex Chinese board game Go.
AlphaGo, the AI programme developed by Google DeepMind, triumphed over world champion Lee Sedol.
The win is significant because the 3000-year-old Chinese game, one of the most creative and complex to be devised, has been difficult for computers to understand.
The near-infinite number of board positions in Go requires players to rely on intuition in making their moves. AlphaGo was designed to mimic that intuition in tackling complex tasks.
AI experts had predicted it would take another 10 years for computers to beat professional Go players, until AlphaGo beat a European Go champion last year.
Mr Sedol has four more chances to beat the computer programme between March 10th-15th. At stake is $1m in prize money, which Google said it will donate to charity if AlphaGo wins.