Google’s AlphaGo artificial intelligence has secured its fourth win over a master player, in the final of a five match challenge.
Lee Se-dol, one of the world’s top Go players, won just one of the matches against Google’s AI, missing out on the $1m prize up for grabs.
In Go, players take turn placing stones on a 19-by-19 grid, competing to take control of the most territory.
The game is considered to be much more challenging for computers than chess.
The five match challenge began in Seoul on 9 March, where AlphaGo scored its first victory.
After losing the second match, Lee Se-dol said he was “speechless” adding that the AlphaGo machine played a “nearly perfect game”.
In the third game commentators said that Lee Se-dol had brought his “top game” but that AlphaGo had won “in great style”.
Google’s winning streak means it will pocket the $1m (£702,000) prize on offer.
But Lee Se-dol did win the fourth game, after which he said: “I’ve never been congratulated so much because I’ve won one game.”
The AlphaGo system was developed by British computer company DeepMind which was bought by Google in 2014.
It has built up its expertise by studying older games and teasing out patterns of play.
Analysis by Dr Noel Sharkey, AI expert
To beat one of the world’s top players, Deep Mind used a mixture of clever strategies to make the search much smaller.
Does this mean AI is now smarter than us and will kill us mere humans? Certainly not.
AlphaGo doesn’t care if it wins or loses. It doesn’t even care if it plays and it certainly couldn’t make you a cup of tea after the game.
Does it mean that AI will soon take your job? Possibly you should be more worried about that.
What is Go?
Go is thought to date back to several thousand years ago in China.
Using black-and-white stones on a grid, players gain the upper hand by surrounding their opponents pieces with their own.
The rules are simpler than those of chess, but a player typically has a choice of 200 moves, compared with about 20 in chess – there are more possible positions in Go than atoms in the universe, according to DeepMind’s team.
It can be very difficult to determine who is winning, and many of the top human players rely on instinct.