A world has retired because he has decided humans cannot beat at his game. The champion is Lee Se-Dol from South Korea. He was world champion at the , strategy board game Go. Some people compare Go to chess. Mr Lee is the only person in the world to beat Google's AlphaGo computer algorithm. This is a A.I. computer program created by Google to play Go. Mr Lee, an 18- world champion, told reporters this week that: "Even if I become the number one, there is an entity that cannot be defeated. With the of A.I. in Go games, I've realized that I'm not at the top even if I become the one."
The game of Go originated in China around 3,000 years . Today, it is played in China, Japan and South Korea. It is believed to be the oldest game in the world. In 2016, the International Go Federation said it had 75 member , and that over 46 million people knew how to play Go. Mr Lee started playing at the of five. He turned professional seven years later, when he was 12. He played five games against Google's AlphaGo and lost four of . He said his one was because of a "bug" in the program. The bug did not know what to do when Mr Lee made a "" move. Today's Go programs are much more powerful than the that beat Mr Lee.