South Korean Go master Lee Se-dol was the only human ever to defeat artificial intelligence (AI) Go player AlphaGo.

DeepMind, the artificial intelligence research arm of Google parent company Alphabet, created the AlphaGo algorithm. Go is an ancient Chinese strategy board game somewhat akin to chess. Players use black or white pieces and try to capture the opponent’s stones. In 2016, Go master Lee Se-dol managed to win one game in a tournament of five games playing against the AlphaGo Artificial Intelligence algorithm. Lee has recently retired, admitting that AI was unbeatable at Go.

Lee Se-dol vs. AlphaGo

However, Lee charitably attributed his sole 2016 win to a bug in the programming of the algo. Lee made an unexpected move at white 78, which tripped up AlphaGo.

“My white 78 was not a move that should be countered straightforwardly. Such a bug still occurs in Fine Art (a Chinese Go-playing computer program). Fine Art can hardly be defeated even after accepting two stone handicaps against humans. But when it loses, it loses in a strange way. It’s due to a bug,” Lee said.

AlphaGo even more powerful in new avatar AlphaGo Zero

AlphaGo’s expertise is based on machine-learning of 30 million moves by human experts. At one stage, it could correctly predict what its opponent would do 57 times out of 100.

But its successor, AlphaGo Zero, is a whole new ball game altogether. It reportedly learned to play by practicing against itself!

No prizes for guessing the outcome of a match between the two algorithms: AlphaGo Zero won all the 100 games it played against AlphaGo.

Lee Se-Dol versus AlphaGo: Lee’s going-away game

Never mind Lee’s defeat to AlphaGo. To commemorate his retirement, Lee will play a South Korean artificial intelligence called HanDol next month. HanDol has already bested South Korea’s top five players. Though Lee will get an advantage, he doesn’t seem confident of his chances.

“Even with a two-stone advantage, I feel like I will lose the first game to HanDol,” he says.

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