South Korean professional Go player Lee Sedol, right, puts a stone against Google's artificial intelligence program, AlphaGo, as Google DeepMind's lead programmer Aja Huang, left, sits during the match in Seoul on March 9, 2016.(Photo/Agencies)
South Korean Lee Sedol, the world champion of the ancient Chinese board game Go, turned aggressive in his strategy for the third of a historic five-game Go match with Google's computer program AlphaGo after his successive losses in the first two games.
Lee and AlphaGo launched the third game at 1 p.m. local time (0400 GMT) on Saturday at Four Seasons hotel in Seoul.
Playing Black, Lee put his starter at the upper-right flower spot, placing his next marker at a position right beside the upper-left flower.
AlphaGo started off the game, with the first two white stones placed both on flower positions, a strategy seen in the first match.
The human champion entered into an aggressive battle from the very beginning to dominate the game in the first half.
Following his second defeat, Lee told a press conference on Thursday that his winning possibility would likely rise if he gets dominant in the first half.
The 33-year-old allegedly analyzed AlphaGo's strategy all night after the second loss with his South Korean Go professional colleagues, reaching a conclusion that he can win only when he dominates in an early phase.
Lee has lowered his confidence over the historic match, saying during the Feb. 22 press conference that AlphaGo would by no means win any game. He got less confident on Tuesday about a 5-0 victory.
After the first defeat on Wednesday, Lee expected a 50-50 victory and lowered his confidence further on Thursday that he would do his best to win at least one game.
One commentator said that AlphaGo showed "innovative, adventurous and dangerous-look moves" in the first two matches, noting that the computer program seemed more confident in the latter half.
The AI boasts of a deep learning capability to learn for itself and discover new strategies by playing games against itself and adjusting neural networks based on a trial-and-error process known as reinforcement learning.
Lee is regarded as one of the greatest Go players in the world as he won 18 world championships for 21 years of his professional career. He recorded a winning rate of about 70 percent with 47 victories in professional matches, while AlphaGo posted a 99.8 percent rate with hundreds of victories and only one loss.
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.
