@12401
"It's also important to note that other than discarding probably lost positions, we can also discard any position that feels yucky." ++ That is what I did inspecting the random sample of 10,000 positions, e.g. this one:
That is how I reduced from 10^38 to 10^38 / 10,000 = 10^34 positions.
"pretty much any opening ICCF GMs don't play we can probably safely ignore"
++ This is debatable. They played Ruy Lopez: open, closed, Berlin, Italian, Vienna, Petrov both Nxe5 and d4, Sicilian Najdorf, Moscow, Closed, French Winawer and Steinitz, Queen's Gambit Slav and accepted and declined, Catalan, Nimzovich Indian Defense, Queen's Indian Defense, Grünfeld Indian Defense, Kings Indian Defense, Reti, English...
They did not play Scotch, Four Knights, Sicilian Alapin, French Tarrasch, Advance, or Exchange...
"Strong players play good openings, and bad players play bad openings."
++ Yes, they try to win, not lose, or scrape a draw.
"A solution will contain strong openings" ++ Elroch will insist on 1 a4 and 1 e4 e5 2 Ba6.
"ICCF GMs have already solved chess" ++ Almost. It is redundant, but not yet complete.
Their effort of 90 CPU/server * 2 server/finalist * 17 finalists * 2 years = 6120 CPU years is 61 times more than the 50 CPU * 2 years = 100 CPU years Schaeffer used to weakly solve Checkers.
"Any position they don't play in one of their games we can also discard as a lost position."
++ Or a draw without prospect. 1 a4 is enough to draw, but makes it easy for black.
@12402
"I'm assuming the ICCF top players all have access to the same engines and databases as each other - so isn't it rather expected that they'll all be drawing each other in their games?"
++ All ICCF World Championship Finalists qualified for the Finals through qualifiers, so they are of comparable strength. They have access to more or less the same hardware and software and resources. However, in previous years they also were of comparable strength and also had access to about the same hardware and software and resources, and nevertheless there were decisive games, every year fewer. Now none: 110 draws out of 110 games.
That means they were approaching perfect play in previous years and now have reached it.