by Chris Garlock

During a long walk around Seoul on Monday — the day off before the Google DeepMind Challenge final game Tuesday

between Lee Sedol 9P and AlphaGo — Michael Redmond 9P was still thinking about the game from the previous day, in which Lee had finally snatched victory from the jaws of defeat. In reviewing the game carefully, he was convinced that Lee’s “brilliant” move 78 — which had won the game — didn’t actually work. Somehow, though, it had prompted a fatal mistake by AlphaGo, which top members of the DeepMind team were still trying to understand, and had reviewed key points with Redmond after the match and then again at breakfast Monday morning. While Redmond was fascinated with the move’s many complicated variations and trying to understand what had happened to AlphaGo, he was also thinking about Honinbo Shuwa, the 19th century Japanese professional go player admired by modern professionals for his light, flexible play, and mastery of “amashi,” taking territory early and then invading or reducing the opponent’s resulting area of influence. Which is exactly the strategy employed by Lee Sedol against AlphaGo in the fourth game on Sunday. “Shuwa would just jump into huge moyos and lay waste to them,” Redmond said as we walked past the Changgyeonggung Palace. “He’d just be kind of floating around there and still taking territory while being attacked. It was just sort of impossible to kill Shuwa’s stones.” Lee Sedol was doing things a little differently, Redmond noted. “He was taking profit and taking profit and then invading at the last minute. He’s been trying this strategy since Game 2 and it hasn’t been working but it finally did in Game 4.” In the final game, in which Lee will take black, “I think that Lee has the idea that he can use the amashi style, which is usually used when playing white, to take territory, allow AlphaGo to build a big moyo and then jump in.”

Garlock is the Managing Editor of the American Go E-Journal. photo: Redmond (left) with DeepMind team members David Silver (next to Redmond), Chris Maddison (second from right) and Thore Graepel (far right), reviewing Game 4 Sunday night.

Click here for Redmond’s Match 3 Game Highlights and here for the Match 4 Livestream commentary by Michael Redmond 9P with Chris Garlock. Click here for complete commentaries on games 1-4, as well as brief game highlights for each round.

The fifth and final game in the 5-game Lee Sedol-AlphaGo match will be Tuesday, March 15, 1P KST (Monday night 9p PST, midnight EST). The match will be livestreamed on DeepMind’s YouTube channel with commentary by Redmond and Garlock. And catch Myungwan Kim 9P’s commentary with Andrew Jackson starting at 10P PST on the AGA’s YouTube Channel.