Re:No reachable chess position with more than 218 moves
by mtremsal on Friday September 26, 2025 @09:26AM
(#45386269)
Then white plays 1 stone, capturing all the black stones at once, essentially resetting the game with a 360 points lead.
(black goes first, white has Komi, so really a 260+komi points lead)
Re:No reachable chess position with more than 218 moves
by tromp on Friday September 26, 2025 @09:44AM
(#45386430)
White cannot play on the last empty point as this would be suicide, which is prevented by the (assumed) superko rule forbidding repetition of the empty position.
Re:No reachable chess position with more than 218 moves
by GabrielBen on Friday September 26, 2025 @09:27AM
(#45386278)
A game of Go can be legally infinite due to recaptures. (player passes 360 times, then eats the entire board and it starts over).
It's also a natural infinite game due to Kos which can be the best move to play. This requires a set of extra rules to prevent. (Ko, superKo, triple kos, etc)
The maximum number of possible next moves is 361, which happens only in the initial empty position.
The 361 hardest-to-reach positions (assuming logical rules like [2]) are all the positions with 360 white stones and 1 empty point. these take 2*361 = 722 ply to reach, with black passing all their turns.
And these answers were found without checking all 208168199381979984699478633344862770286522453884530548425639456820927419612738015378525648451698519643907259916015628128546089888314427129715319317557736620397247064840935 legal positions :-) [1]
[1] https://tromp.github.io/go/legal.html
[2] https://tromp.github.io/go.html