On Mar 16, 8:39*pm, " wrote:

First, what Schaeffer did is to show that freestyle (unrestricted)
checkers is an absolute draw.

He has not analyzed all of the 3-move restriction openings so he has
not proven that tournament checkers is a draw. *He has proven that
some of the 3-movers are a draw, and will likely eventually show that
all 156 of the accepted tournament choices are a draw (the other few
are almost certain losses and are not used). *Of course, there could
be a deeply-buried surprise in one or more of the 156, but with the
amount of other computer analysis done to date, it's not very likely
--- but it hasn't been categorically proven yet.

I wouldn't be all that surprised if instead he finds that some of the
156 accepted three-move tournament choices are not draws. After all,
the ones that were rejected were obvious losses, so openings that
provided one player sufficient advantage to narrowly force a win with
perfect play might not have been noted.

I realize that this is a fairly large advantage, though, and that
might mean it would have been suspected, but then the fact that
freestyle checkers was a draw wasn't known for certain until it was
proved.

John Savard