A computer defeated China's top player of the ancient board game Go on Tuesday in the latest test of whether artificial intelligence can master one of the last games that machines have yet to dominate.

Ke Jie, a 19-year-old prodigy, is due to play a three-game match against AlphaGo in this town west of Shanghai. During the five-day event, the computer also is to face off against other top-ranked Chinese players.

AlphaGo beat Ke by a half-point, "the closest margin possible," according to Demis Hassabis, founder of DeepMind, the Google-owned company that developed AlphaGo.

"AlphaGo wins game 1!" said Hassabis on Twitter. "Ke Jie fought bravely and some wonderful moves were played."

Go, which originated in China more than 25 centuries ago, has avoided mastery by machines even as computers surpassed humans in most other games. They conquered chess in 1997 when IBM's Deep Blue system defeated champion Garry Kasparov.

Go, known as weiqi in China and baduk in Korea, is considered more challenging because the near-infinite number of possible positions requires intuition and flexibility.

AlphaGo Ke Jie Deepmind
It was the closest result yet in a human vs AI game of Go. Deepmind.com

The rules of Go

Players take turns putting white or black stones on a rectangular grid with 361 intersections, trying to surround larger areas of the board while also capturing each other's pieces. Competitors play until both agree there are no more places to put stones or one quits.

Players had expected it to be at least another decade before computers could beat the best humans due to go's complexity and reliance on intuition, but AlphaGo surprised them in 2015 by beating a European champion. Last year, it defeated South Korea's top player, Lee Sedol.

AlphaGo was designed to mimic such intuition in tackling complex tasks. Google officials say they want to apply those technologies to areas such as smartphone assistants and solving real-world problems.

Human players were startled when AlphaGo scored its first major upset in October 2015 by defeating a European champion.

AlphaGo defeated Lee, the South Korean, in four out of five games during a weeklong match in March 2016. Lee lost the first three games, then came back to win the fourth, after which he said he took advantages of weaknesses including AlphaGo's poor response to surprises.

Go is hugely popular in Asia, with tens of millions of players in China, Japan and the Koreas. Google said a broadcast of Lee's match with AlphaGo was watched by an estimated 280 million people.

Players have said AlphaGo enjoys some advantages because it doesn't get tired or emotionally rattled, two critical aspects of the mentally intense game.