Lee Sedol came back strong today with a nice win over AG. The game started off similar to Game 2 , and it appears that Lee Sedol made a brilliant move on the 78th turn that made the position complicated and to which AG did not come up with a goodresponse. I guess this game will be studied quite a bit by the Deepmind team. It will be interesting to see what the program will learn from this game and how it will learn from this. Did Lee actually find a weakness in the program that cannot be fixed in short order? Next game is on Tuesday.
Summary at http://www.theverge.com/2016/3/13/11184328/alphago-deepmind-go-match-4-result
and here is the video with commentary on youtube: