So God plays backwards, so to say. He does what’s called retrograde analysis, “a technique employed to determine which moves were played leading up to a given position” (cf. https://en.wikipedia.org/wiki/Retrograde_analysis)

I had a vague intuition of doing the same (going backwards) to generate the winnable Solitaire card deals, but I didn’t get far with it… Does anyone have experience/ideas on that? FTR: a similar discussion on X, started recently by Jonathan Blow: https://x.com/Jonathan_Blow/status/1865520149891346634

I ended up generating totally random deals, then filtering-out those unsolvable by an algorithm of mine (described at https://FreeSolitaire.win/strategy#remarks). It’s fast & good enough to run on-the-fly, when a player starts a new game. But this isn’t an intellectually satisfying solution.

Note that “The probability of being able to win a game of Klondike with best-possible play is not known, and the inability of theoreticians to precisely calculate these odds has been referred to by mathematician Persi Diaconis as "one of the embarrassments of applied probability"” dixit https://en.wikipedia.org/wiki/Klondike_(solitaire)#Probabili...

We need another genius like Ken Thompson for Solitaire!