AlphaGo vs. Lee Se-dol: Game Three

This morning, Lee Se-dol lost a third and deciding game in the challenge match against Google DeepMind’s AlphaGo. The fourth and fifth games will be played but the prize goes to the programme and the prize money will be paid to various benevolent causes.

The game started with a high ‘Chinese’ fuseki which was soon broken up by a vital battle that affected the whole board, a product of Lee Se-dol’s aggressive style and AlphaGo’s refusal to capitulate. Black fought for his heavy and inefficient stones but white, played by the bot, acquired a huge territory that black simply couldn’t match. In desperation, black invaded and a scuffle lead to a complicated situation with multiple Ko fights. Black resigned when it became clear that his stones were lost and, elsewhere on the board, the cost of the scrap became too great to bear.

One incontrovertible fact was proven during the match: AlphaGo does not struggle with Ko fights in the slightest. AlphaGo showed that it can handle extremely tricky Ko situations that play havoc with the game-tree and would have completely flummoxed its ancestors, the MCTS engines of yester-year.

Lee Se-dol admitted that AlphaGo defeated him, taking ownership of his defeat and lamenting that he did not show us a better game, today. He said that today’s defeat was his defeat, not a defeat of human beings.

Michael Redmond, the 9 dan professional westerner who provided the official English commentary during the match, brazenly declared that AlphaGo “beat Lee Se-dol at his own game!” In front of a veritable army of reporters, in the ballroom of a hotel in down-town Seoul, he went on to suggest that AlphaGo would herald a “third revolution” in Go opening theory, mentioning AlphaGo in the same sentence as Honinbo Dosaku and Go Seigen, two legendary human players who sparked extensive, novel innovation in the fuseki in the past.

When a member of the audience questioned Redmond’s prophecy, Lee Se-dol answered that he thought AlphaGo is not at the level of the so called ‘Divine Gods’ and described the bot’s play as ‘different’ and ‘superior at times.’

Meanwhile, in the Go community, speculators questioned whether Lee Se-dol (9 dan professional) was, in fact, the best player to champion humanity in this duel against the machine. Some pointed to his aggressive and frequently precarious fighting style and hypothesised that AlphaGo’s cold and heartless play was ideally suited to winning in such situations – situations in which mere mortal, human professionals might become flustered or overwhelmed by the complexity. Some suggested that calmer, more placid players might fare better against the A.I.

Lee Se-dol reassured the audience at the post-match conference that AlphaGo is not yet perfect. I believe him. If he does not defeat AlphaGo, another will, but I do hope that he shows us the way over the course of the next two games.