On
March 15, 2016, AlphaGo beated Lee Se-dol(9-dan pro) in the fifth game. Although lost the 4th game to Lee Sedol two days ago, AlphaGo won the five-game series with the total score 4:1.
Now get its professional ranking as the second place in the world after the winning, only after Ke jie, who is the stand on the top at the age of 18.
“AlphaGo has a proper ranking now (thank you for the loss, Lee Sedol - the ranking algorithm doesn't work well with wins alone!). 3533, 4th in the world. Up for a game, Ke Jie?” posted by Raia Hadsell, the Research Engineer of DeepMind Team, on her personal facebook pageon March 13.