TalkChess.com

[Daniel Shawul]

Infact their claim is that 10^18 unique positions (state space complexity) are possible to solve not that many number of variations which I thought it was. The game tree complexity for checkers is actually about 10^30 to 10^40. For chess using Rybka with a BF of 1.8 , the number of variations ( game tree complexity ) is 10^18 already, the state space complexity would be much lower. So it is not only probabilisticaly solvable but also by a huge margin at that . It is stated 10^18 unique positions are possible which is taken from checkers effort.

If you talk about real solutions there is no need to mention Rybka at all. They suggested using something much weaker than even TSCP ... Many people were asking which version of Rybka was used for the experiment which shouldn't have mattered if you were after exact proofs. So it is either no 99.99999% claim or if you do that don't use that lame explanation which assumes use of dumb alpha-beta.
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