syzygy wrote:Current top engines (and in fact any regular chess engine developed over the last 70 years or so) have nothing to do with weakly solving the game.
That's a very strong incorrect statement. Alpha-beta search was extensively used in the checkers proof, along with tablebases (which you know about) and a "proof manager" (analogous to Cerebellum) to handle graph history interaction and find the most forcing continuation:
"The manager uses the new approach of iterating on the error in Chinook's heuristic scores. The manager uses a threshold, t, and temporarily assumes that all heuristic scores ≥ t are wins and all scores ≤ –t are losses. It then proves the result given this assumption. Once completed, t is increased to t+∆, and the process is repeated. Eventually t reaches the value of a win and the proof is complete. This iterative approach concentrates the effort on forming the outline of the proof with low values of t, and then fleshing out the details with the rest of the computation."
Of course one must still prove a lot of positions, which is vastly easier in checkers because of the shorter distance to the tablebase. Nevertheless, it's absolutely clear that both 1.e4 and 1.d4, and more than one reply to each, draw. And since we know it, proving it is not inconceivable.
-Carl