The late Takagawa Kaku, who was Honinbo for nine consecutive terms in the 1950s, and was a title contender until the 1970s) said that he would have to take four stones from God to make it an even game. Perhaps this is a realistic estimate. I don't know of any professional who claims to be near perfect play. They all (and I mean all who have ever commented on this subject) claim that their go needs substantial improvement
Great modern players like Fujisawa Shuko and Kobayashi Koichi claim that Honinbo Shuei (died 1907) was stronger than they are.
Korean Go is more territory-oriented than influence-oriented. Yamashita Keigo 7-dan (the 21-year-old who won the Gosei title from Kobayashi Koichi) often plays a 5-5 and 5-4 combination on one side of the board. He is probably the most recent strong player to adopt an influence-oriented game. However, most title holders in Japan, Korea, and China play a tight territorial game.
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