Alphago, a cutting-edge computer programme designed by Google, will face off in the Google DeepMind challenge against Lee Sedol, the world champion of Go

The Google DeepMind challenge match, taking place in Seoul on Wednesday, will pit the world’s top player of the ancient Chinese board game against the world’s most sophisticated Artificial Intelligence programme.

Here is everything you need to know about this clash between advanced technology and old-fashioned human wit.



Google throws down the gauntlet. But can anyone beat its computer at Go? Read more

What is Go?

Go is a roughly 3,000 year-old board game thought to have originated in what is now China. Its rules have changed little over its long history, and it is still a widely enjoyed pastime throughout East Asia. Though Go isn’t played much in the West, in parks across China, South Korea and Japan, it is common to find groups of men huddled around boards covered in the game’s circular black and white tiles.



How do you play it?

Every game of Go features two players, one using black tiles and the other using white tiles. At the start of the game, the board is empty, and players take turns placing one stone at a time on the board, trying to gain territory by arranging stones in strategic shapes or patterns. Another key objective is getting control of their opponent’s stones by surrounding them on all sides.



The game is played on a grid; the winner is the player whose pieces occupy the larger number of the grid’s intersecting points at the end of the game.



Why is it so complicated?

At first glance, Go seems fairly simple. Unlike chess, all the pieces are the same, and once played, cannot be moved around the board.

But that surface level simplicity is somewhat deceptive, as there are many ways players can deploy those pieces. Go has trillions of possible moves; according to the British Go Association, at the opening of Chess there are 20 possible moves. In Go there are 361 possible moves.

These almost endless possibilities make it difficult to craft in advance and follow a particular strategy. Mastering the game means using intuition to react to any number of possible twists or turns a game can take, depending on an opponent’s moves.

Demis Hassabis of Google has called Go “the most profound game that mankind has ever devised,” describing it as “primarily about intuition and feel rather than brute calculation which is what makes it so hard for computers to play well.”

Why play against an AI machine?

Creating a program that can play Go at the highest level is one of the most challenging tasks tackled by AI professionals. Computer programs have long been able to beat the top human players in games such as chess and checkers, but mastering the reactive and intuitive nature of Go is more difficult.

Last October Alphago scored its first victory over a professional Go player, European Go champion Fan Hui, a feat that experts had predicted was something like a decade from being possible. AlphaGo’s advancing proficiency at Go therefore provides a glimpse into how soon and to what extent computers will be able to master intuitive tasks.

What does it mean if the machine wins?

AlphaGo will square off against the 33-year-old Lee Sedol a total of five times (9, 10, 12, 13, 15 March) at a hotel in Seoul. At stake will be $1m in prize money, which Google has said it will donate to charity if Alphago wins.



Even though Alphago is fresh off a victory over Fan Hui, Lee has said he is confident he will come out on top. Since AlphaGo’s victory over Hui, the Go cognescenti has pointed to mistakes the program made that a stronger player, such as Lee, would have capitalized on. Lee has won 18 international Go titles, second only to his fellow South Korean Lee Chang-ho (no relation).

At the press conference confirming the details of the match, Lee exuded confidence. “I don’t think it will be a very close match,” he said.

But if Alphago can best him, it will be a watershed moment for AI with only one genuine precedent: Deep Blue’s victory over Kasparov in 1997.