The announced retirement of Go champion Lee Sedol
has sent shock waves through not only the Go community. In 2016, Lee, who was considered the best Go player in the world, lost a set of matches 4-1 against AlphaGo, an AI system developed by the Google-owned company DeepMind.
The fourth showdown between Lee Se-dol (right) and AlphaGo, the artificial intelligence designed by Google’s London-based firm DeepMind, in 2016. Photograph: EPA
“With the debut of AI in Go games, I’ve realized that I’m not at the top even if I become the number one through frantic efforts,” Lee told Yonhap News in Korea. “Even if I become the number one, there is an entity that cannot be defeated.” (https://www.vice.com/en_us/article/qvg7pb/go-pro-lee-sedol-quits-says-ai-is-too-tough-to-beat)
‘I kind of felt powerless’
Lee told the press at the time he had “misjudged” AlphaGo’s abilities: “I apologise for being unable to satisfy a lot of people’s expectations. I kind of felt powerless.”
Lee’s first realisation that AlphaGo was playing at a level w-a-a-a-y above him appears to have come at move W107 in Game 1, as noticed by this thread on Reddit. We’ve made a gif of the move below. AlphaGo, playing in white, drops a stone on the right side of the board about halfway up, at the lower diagonal from three black stones arranged vertically. It’s completely unexpected because it seems to be unconnected with the rest of the white strategy on the board.
Normally, Lee stays quite still during games, as he stares at the board and thinks.
Not this time.
‘Lee literally dropped his jaw. [His] reaction was not aired in the official YouTube live stream’
Redditor “balancetraveller” wrote:
“Lee literally dropped his jaw at W102. Lee’s reaction was not aired in the official YouTube live stream. The move is considered the tide-turning move.”
You can see a video of the move here, at timestamp 2.30.20. This gif shows that at first he seems paralysed for several seconds. Then he rocks backwards in surprise, before running a hand over his hair in dismay. For Lee, that’s a lot of physical drama in comparison to his normal, stoic demeanour:
It was Game 2 when AlphaGo’s superiority was confirmed, as noted by Wired. Move 37 by AlphaGo baffled everyone who saw it:
[European champion] Fan Hui thought the move was rather odd. But then he saw its beauty. “It’s not a human move. I’ve never seen a human play this move,” he says. “So beautiful.”
AlphaGo, playing black, puts a stone on the right-middle of the board, at a diagonal to an isolated white stone. This next photo shows Lee’s reaction: He gets up from his chair and walks away from the board.