(I translated this article written by Lee Sedol himself, which originally appeared on March 18 on DongA.com news http://news.donga.com/3/all/20160318/77064593/1 I tried to avoid liberal translation, so the translated sentences may be a bit rough. I will translate subsequent articles when I have time.)

AlphaGo Had Become Unbelievably Stronger in 5 Months… Could Not Imagine the Critical ‘102nd Move’

[Lee Sedol, after the 'Match of the Century’]

[Lee Sedol’s Review on the Week with AlphaGo] Absolute Defeat at the First Contact

AlphaGo’s haengma in the left bottom part seems to be a bug… after the match, I told Google

<<The one-week match between Lee Sedol 9 dan and Google AI AlphaGo felt like a dream. While the world was swept by the desperation of humans being defeated by the machine and the fear that the machine is too strong, there was only one who did not lose hope. Lee 9 dan, the adventurer, demonstrated the victory of the fighting spirit, and achieved the turn-around that moved all Koreans. How did he do during the week? The critical moves that Lee Sedol thinks of and episodes about the matches are described in five articles.>>

Two days before the AlphaGo match, the 7th, during the award ceremony for the Myunginjeon victory, I said “if I lose once to AlphaGo, it is my defeat”. Indeed I did not know AlphaGo.

After I lost the first match, people brought up ‘unfairness from information asymmetry’. That is, it is unfair that my game records are known to AlphaGo, but I did not have a chance to see AlphaGo’s game records that reveal its strength. I do not agree. Even for a normal match, when I play with a player that I’ve never played, I play without any information on the player. I can lose when I play with a player who is unexpectedly strong.

I read the game records that AlphaGo played with Fan Hui last October. As I said repeatedly, AlphaGo was not my match at that time. However, I have always thought that it is impossible to understand the opponent just reading game records. The ample intangible information that I perceive during a real match cannot be understood from a game record.

AlphaGo is an AI, a machine, but she has her own way of playing the game. In the first match, AlphaGo played a few moves that humans can hardly understand. If I read such moves in the game record before the match, it is highly likely that I would come to severely underestimate AlphaGo’s ability. Information asymmetry is only an excuse. An adventurer must overcome such thing.

In the first match, I failed in the beginning, and there was no moment that I was winning. However, there was a moment that I could catch up with AlphaGo, narrowing the gap. It was when I made a big territory in the left bottom. After the match, I told Google that AlphaGo’s heangma in the left bottom was almost like a bug.

The right side white 1 (102nd move), which is often denoted as AlphaGo’s winning move, proves that the match had become a tough game. It seems that AlphaGo plays a bold move like this because she judges that she could not win in a peaceful way. During the post-game review, I figured that if I investigated the move like ‘가’ before the white 1, it could reduce the destructive power, but I could not imagine that AlphaGo would play a move like this.

After a move like this, it was hard to win. I made a mistake in losing points while treating the right bottom, but even if I did not make the mistake, I was losing by half to one and half point.

AlphaGo plays strange moves, but it had the capability to venture at the right time. I lost the first match, but I did not feel too much regret. I lost because I was ignorant, I lost because I misjudged, I lost because I failed in the close combat in the beginning. I was shocked by the fact that I unexpectedly lost, but it happens in human matches as well. Rather, it was like elixir that awakened me for the second match.