https://qooah.com/2016/03/12/alphago-%e6%be%84%e6%b8%85%e6%b2%92%e8%b7%9f%e6%a3%8b%e7%8e%8b%e4%bd%9c%e7%a7%98%e5%af%86%e5%8d%94%e8%ad%b0/