By Sunny Um WIRED Korea

Lee Sedol, a grandmaster of Chinese board game Go, lost the final of a three-game match against artificial intelligence (AI) rival, HanDol. He lost two games in a row after winning the opening one.

The final game was held in Lee’s hometown, Sinan-gun, South Jeolla Province last Saturday. The previous games took place in Seoul last Wednesday and Thursday.

In the faceoff, Lee put two of his stones first, 10-to-13-point advantage, which was given to him as he had lost the previous game.

Lee and HanDol had an intense fight at the lower part of the board for over two hours. Both players did not make any big mistakes, as they did in the previous games. Lee Young-gu, a professional Go player commented: “Both players fought each other with excellent skills.”

However, HanDol was strong in its defense. Lee launched a few powerful attacks but failed to break through its defense line.

In Game One, Lee won the fight with a move that hit a bug in HanDol’s program. In the second game, HanDol seized a chance to win when Lee made a critical mistake at an early stage.

In a post-game review, Lee told the reporters that he must have lost because he was “badly rattled” after HanDol made unanticipated moves.

“Even though I lost today, I was happy because I had a good fight. It’s nice that I had such a match,” said Lee.

Go, or “Baduk” in Korean, is a Chinese game played by two people, putting black or white stones on a grid board. The player who dominates territory wins the game.

HanDol is an AI Go program developed by NHN Entertainment, a tech giant that operates the biggest web portal, Naver. The company programmed HanDol to devise optimal moves, using the big data collected since 1999. HanDol defeated the top five Korean Go players in January.

NHN said it was confident that the latest version of HanDol outperforms the AI player built by Google DeepMind, AlphaGo, which defeated Lee in 2016.

Lee announced he would retire after the match with Chinese Go player Ke Jie in March.

Lee, who now regards himself an amateur Go player, said he has no specific plan for his future.