The emergence of the computer Go player AlphaGo is "tantalizing" as it showed unheard-of moves and may take humans to a higher level of the ancient board game, the president of the American Go Association said Wednesday.

Andrew Okun, president of the New York-based AGA, said he was shocked and saddened to see South Korean Go master Lee Se-dol losing to the artificial intelligence program developed by Google's DeepMind, but that AlphaGo's emergence could end up being good for the game.

"Among experienced go players, as much as they wanted Lee to hold up the human end of the match, the revelation that there is a new player making new moves is tantalizing," Okun said in an email interview with Yonhap News Agency from Seoul that he visited for the five-game series.

"Maybe there is another level of Go better than the one we're playing at, one we haven't reached yet, and maybe AlphaGo or other software can take us there," he said.

Go is a strategy board game in which two players place white and black stones on a 19 by 19 board alternately in a race to encircle more territory. It is considered the most complex game ever devised by humans due to its infinite number of variables.

Lee, 33, one of the greatest Go players with 18 world titles, lost what was dubbed "the match of the century" 4-1 to the self-learning program, sending shock waves through the global Go community and raising questions about how far artificial intelligence can go.

"He was playing for all of us in the Go community and trying to do his best. It was a great demonstration of fighting spirit, but we may just be at the point where the computers are going to be better than us," said Okun, whose Go strength is about amateur fourth-dan.

Okun, who took office as AGA chief in 2012, said that it was clear that the previous version of AlphaGo, which beat Chinese second-dan player Fan Hui in October, could be beaten by Lee, but the program appears to have since made enormous proress in learning.

"We had no information publicly about how fast AlphaGo was improving," he said. "If the player had been human, we could have guessed how much improvement there would be in six months. With a self-teaching computer, how would we know if getting to Lee Se-dol 9p's (professional dan) strength would take a thousand years or 45 seconds?"

One of the most heartbreaking and shocking moments in the series was when Lee conceded defeat in Game 1 and sat alone without a counterpart to review the game, a key part of any Go matches, especially among professional players, Okun said.

"I think I was shocked by the moment. When he resigned, it hit me and everyone here harder than I expected," he said. "The most melancholy moment of all for me was when Lee realized it was time to resign, put the white prisoners back on the board and then reached out to the stones to begin reviewing," Okun said.

Review is an iconic moment in any face-to-face Go match and especially one among pros and it is when they go from opponents back to friends and fellow go community members, and appreciate together the game they just played and cooperate to find better ways to play, he said.

"This time, there was no one across the board, just the DeepMind engineer, who probably felt it was not appropriate for him to review with Lee. Lee was just alone with his questions. Heartbreaking," he said.

The games drew big interest from American Go fans as well, he said, with many of them watching the games live despite the day-night time difference. AGA's Youtube commentary broadcasts were the most watched live of any it has done so far, he added.

AGA, with some 2,000 members, is the principal organization promoting and organizing the game of Go in the U.S. A member of the International Go Federation, the association runs a ratings system for American players as well as an email and web news service that is the biggest Go-specific news source outside Asia.

Okun said he is upbeat that the matches will have positive effects on the sport of Go.

"There has been so much publicity it can't help but be good for the game," he said. "I think it will increase the number of players and fans. If the technology becomes available, it will strengthen players and change some of how we think about playing."

The games could also lead to a change in the "nature of being a go master or go pro," he said. (Yonhap)