Aaron Sterling pointed Jon Schafer (the checkers guy!) to my entry and Scott's entry on checkers, and the comments on it. the comments on it. Then Aaron Sterling and Jon Schaefer had an email discussion about the checkers result. Here is the transcript abbreviated.
Please clarify what you mean by checkers being solved.
As you can see from the discussion, there is lack of
what the Science article really meant.
Checkers has been weakly solved. The game is a proven draw and the
gives the sequence of moves for white and black to achieve the draw.
More pointedly: what percentage of the total gametree is now determined?
We considered 1014 positions out of the total search space of 1020.
If the search area was pruned, what were the criteria used for that?
Lines of play that were provably irrelevant to determining the final
result were ignored.
Is there even a
shred of possibility that a "supposedly losing" move could in fact
lead to a
won position, and so certain game lines were improperly excluded
Most significantly, perhaps, is this only a statement about 8x8
does it generalize in any way?
8x8 checkers only. The program can, however, be used to solve any
game of checkers
(it does, in fact, work for an 8x8 variant and 10x10 international