7 man syzygy thing I do not understand (max win distance)

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Dann Corbit
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7 man syzygy thing I do not understand (max win distance)

Post by Dann Corbit »

All the files (including ones with pawns) seem to have 100 as the maximum distance to mate.
But the counter should reset if I move a pawn, castle, or capture a piece.
I do not understand how 100 can be the maximum.

Why is it that no position in the 7 man files has a mate distance greater than 100.
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Sesse
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Joined: Mon Apr 30, 2018 11:51 pm

Re: 7 man syzygy thing I do not understand (max win distance)

Post by Sesse »

Syzygy tablebases are distance-to-zero respecting the 50-move rule (DTZ50), not distance-to-mate (DTM). In other words, the counter is towards the next move that is a capture or pawn move, resetting the 50-move counter. This explains why you can never have “win in 101”, because if you did, it'd be a draw (or a so-called “cursed win”).