Endgame Tablebases (EGTB)
An endgame tablebase is a computerized database that contains precalculated exhaustive analysis of chess endgame positions.
Web Query for Nalimov Endgame 6-men Tablebases.
Here you can check what the outcome of a 6-men position will be.
Thanks to Eugene Nalimov, Andrew Kadatch, Robert Hyatt, Kyrill Kryukov, Nelson Hernandez
for generating, compressing, and publishing the databases and offering them for free.
Or use this website at shredderchess.com
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For 7-men positions there are the Lomonosov Tablebases.
On this website the story about the development of it.
Programmers Zakharov and Makhnichev managed to solve this task in just 6 months
using a new algorithm designed specifically for this purpose and run on the Lomonosov supercomputer based in the Moscow State University.
Syzygy tablebases website for up to 7-men.
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Wikipedia has a interesting article about this subject.
Or look at this ChessProgramming website.
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See also: 8-men Tablebase explorations “opposing 1 pawn” endgames
and 8-men Tablebase: first explorations