Changes

'''Syzygy Bases''', <ref>[http://www.talkchess.com/forum/viewtopic.php?t=47681&start=45 Re: New 6-piece tablebases] by [[Ronald de Man]], [[CCC]], April 10, 2013</ref><br/>

a compact six piece endgame database developed by [[Ronald de Man]], published on April 01, 2013. Since August 2018, '''seven piece''' Syzygy Bases are available after an effort by [[Bojun Guo]] started in March 2018 <ref>[http://talkchess.com/forum3/viewtopic.php?f=7&t=66797&start=472 Re: 7-men Syzygy attempt] by [[Bojun Guo]], [[CCC]], August 19, 2018 </ref>. The generator is released under the [[Free Software Foundation#GPL|GNU General Public License Version 2]], the [[Thread|thread safe]] probing code is released without restrictions <ref>[http://www.talkchess.com/forum/viewtopic.php?t=47681 New 6-piece tablebases] by [[Ronald de Man]], [[CCC]], April 01, 2013</ref> .

=Data=

==Checksums==

Syzygy endgame files may contain 128-bit checksum keys at the end of those files. It also has its own code for checksums (based on Google's cityhash library).

=Search=

==At the Root==

At the [[Root|root]], since pure DTZ50-optimal play (i.e. minimaxing the number of moves to the next [[Captures|capture]] or [[Pawn Push|pawn move]] by either side) can be very unnatural, it might be desirable to let the engine search on the winning moves until it becomes clear that insufficient progress is being made and only then switch to DTZ-optimal play (e.g. by detecting [[Repetitions|repetitions]] and monitoring the [[Halfmove Clock|halfmove clock]]) <ref>[http://www.talkchess.com/forum/viewtopic.php?t=47681&start=8 Re: New 6-piece tablebases] by [[Ronald de Man]], [[CCC]], April 05, 2013</ref>.

=Pros & Cons=

* Hard to understand and contribute to the project. ETGB itself is a hard topic. Syzygy EGTB has also integrated with many advanced techniques/tricks. It is written in old-style C language. All make it become very hard to understand and/or modify to improve or for other purposes

* [[Endgame Tablebases#DTZ50|DTZ50]] metric may lead the engines to win in much longer and ugly ways, compared with [[Endgame Tablebases#DTM|DTM]] one

=Data publish=

[[Jon Dart]] has a fork of Fathom with some bug fixes and enhancements <ref>[https://github.com/jdart1/Fathom jdart1/Fathom · GitHub] by [[Jon Dart]]</ref>, also supporting 7-man <ref>[http://www.talkchess.com/forum3/viewtopic.php?f=7&t=70568 7-man Syzygy support in Fathom] by [[Jon Dart]], [[CCC]], April 23, 2019</ref>.

=Elo gain=

If the engine needs to know the DTZ value (which is only necessary when a TB root position has been reached), the probing code may have to do a 1-ply search to get to the "right" side of the DTZ table.

For 6-piece TBs, DTZ is 81.9GB when storing only the smaller side of each table. Storing both sides might require perhaps 240GB.

=Endgame News=

and further gives some news about early software bugs and glitches concerning [[ChessBase]] products, and the importance of [https://en.wikipedia.org/wiki/MD5 MD5] to check the EGT integrity.

=See also=

* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=71625 Syzygy 7 man advice please] by Barry Clements, [[CCC]], August 21, 2019

* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=71896 Syzygy DTZ data explaination?] by [[Pham Hong Nguyen|Nguyen Pham]], [[CCC]], September 23, 2019

==2020 ...==

* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=73598 Almost perfect DTM tablebase] by [[Dann Corbit]], [[CCC]], April 08, 2020

=External Links=

* [https://github.com/jdart1/Fathom jdart1/Fathom · GitHub] by [[Jon Dart]] (with some bug fixes and enhancements)

* [https://github.com/ljgw/syzygy-bridge GitHub - ljgw/syzygy-bridge: Java bridge to use the Syzygy Tablebases via JNI] by [[Laurens Winkelhagen]] » [[FrankWalter]]

==Online Lookup==

* [https://www.chessdb.cn/queryc_en/ Chess Cloud Database Query Interface] by [[noobpwnftw]] <ref>[http://www.talkchess.com/forum3/viewtopic.php?f=2&t=71764 ChessDBCN] by [[noobpwnftw]], [[CCC]], September 09, 2019</ref>