Lee Sedol says surprised by AlphaGo, expects 50-50 victory

South Korean professional Go player Lee Sedol attends a press conference after the the Google DeepMind Challenge Match against Google's artificial intelligence program, AlphaGo, in Seoul, South Korea, March 9, 2016. Lee Sedol lost the first match. (Xinhua/Yao Qilin)

SEOUL, March 9 -- South Korean Lee Sedol, world champion of the ancient Chinese board game Go, said Wednesday that he was "very surprised" by the capability of AlphaGo, developed by Google's London-based artificial intelligence (AI) subsidiary.

It was his first comment during a press conference after Lee was unexpectedly beaten by AlphaGo in a "match of century" that was widely seen as a representative match between humans and AI.

"I was very surprised because I didn't think I would lose," Lee said. But, he sustained confidence in his victory during the rest of games, saying that he will not be rattled by the defeat of the opening match.

The five-game match between Lee and AlphaGo kicked off on Wednesday, set to run through next Tuesday, at a hotel in central Seoul. The next match is scheduled to be held at the same venue from 1 p.m. local time (0400 GMT) on Thursday.

Lee and AlphaGo played a tight race by the middle of the three-and-a-half-hour match, but the balance was broken as the computer program put an anomalous position in the latter half. Lee resigned following his 186th placing as it became clear that AlphaGo took an unassailable lead.

The 33-year-old said he was surprised by two points, including AlphaGo's capability to resolve difficulties in an early phase and an unexpected anomaly in the latter half.

Though he was shocked at his defeat of the first match, Lee said he played very excitingly, expressing his anticipation for the next match. He said he never regretted accepting the challenge from AlphaGo.

Despite his expression of confidence in the next match, Lee lowered his confidence further and said that he now expects a 50-50 victory. During the Feb. 22 press conference, Lee said AlphaGo would by no means defeat him, and then, he said on Tuesday that his winning rate would not go as far as 5-0.

Lee said he would not be rattled by the first defeat as he won world champions several times, noting that the game just started.

Lee has won world Go champions 18 times in the past 11 years, recording a winning rate of about 70 percent with 47 victories in professional matches. AlphaGo has recorded a 99.8 percent winning rate with 504 victories and only one defeat.

Go originated from China more than 2,500 years ago. It involves two players who take turns putting markers on a grid -shaped board to gain more areas on it. One can occupy the markers of the opponent by surrounding the pieces of the other.