Human Go champion scores 1st win over machine after 3 losses

Lee Sedol's victory over AlphaGo is a reminder that Google's Go-playing program has room for improvement despite winning the first three matches in the best-of-five series and the $1 million prize, which will be donated to charity.

For the final match of the series, scheduled for Tuesday, Lee has offered to play with a black stone, saying it would make a victory more meaningful.

Prior to the series, Go fans, many of them in Asia, believed that the game would prove too complex for the machine to master.

Because there are near-infinite board positions in Go and top players rely heavily on intuition, the popular Asian board game has remained the holy grail for the artificial intelligence community for about two decades, after chess was conquered by computers.