HalfKA information clarification? | Stockfish | Page 1

prisma quest Feb 21, 2026, 9:07 AM

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After a (short) studying about HalfKA, I have some questions (please don’t use AI for answering since I need “sure” information):

What does “A” stand for? Active?
Who invented/first implemented HalfKA? It looks like Tomasz Sobczyk invented HalfKAv2 but I can’t find clear information about HalfKA
Thanks for any help

jovial totem Feb 21, 2026, 9:44 AM

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The A stands for "all"

jovial totem Feb 21, 2026, 10:42 AM

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And Tomasz (Sopel) probably invented it but you can just ask him

prisma quest Feb 26, 2026, 8:00 PM

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@formal crescent can you help to clarify my question please? Thanks

formal crescent Feb 26, 2026, 8:00 PM

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"A" stands for "all" as in all pieces, as in including the king

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if you can call it an invention, then yea, i did it first, as a natural extension of halfkp

#HalfKA information clarification?