Yeah, I think it's possible (although unlikely) for someone to be able to privately build an AI that can compete at the pro level. As you say, they would have a

Yeah, I think it's possible (although unlikely) for someone to be able to privately build an AI that can compete at the pro level. As you say, they would have access to all the papers published by AI researchers. There is always a chance that someone has come up with a new approach. For example, the introduction of Monte Carlo search trees http://senseis.xmp.net/?MonteCarlo http://senseis.xmp.net/?MonteCarlo to computer was hugely successful. An AI on a 9x9 board can now compete at the Dan level. Obviously that's a long way from top-level 19x19 strength but it does show there is always room for a completely new approach.