Google's AI wins final Go challenge

Google's AlphaGo artificial intelligence has secured its fourth win over a master player, in the final of a five match challenge, the BBC reports.

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.