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Add a page for Zahak
'''[[Main Page|Home]] * [[Engines]] * Zahak'''
[[FILE:zahak_logo.jpeg|border|right|thumb| <center>Zahak's Logo - Designed by Nasrin Zaza [https://www.linkedin.com/in/nasrin-zaza]</center>]]
'''Zahak''',<br/>
a [[UCI]] compliant [[:Category:Open Source|open source chess engine]] by [[Amanj Sherwany]], written in [[Go]], licensed under the [[Massachusetts_Institute_of_Technology#License|MIT License]] and first released on [https://en.wikipedia.org/wiki/GitHub GitHub] in February 2021 <ref>[https://github.com/amanjpro/zahak/releases/tag/0.0.1 Release Zahak 0.0.1 · amanjpro/zahak · GitHub]</ref>.
Since version 7, Zahak's hand crafted [[Evaluation Function | evaluation function]] is replaced with an [[NNUE | NNUE style]] evaluation, which is trained by a from scratch written trainer, that is written in [[Go]] as well<ref>[https://github.com/amanjpro/zahak-trainer amanjpro/zahak-trainer · GitHub]</ref>. The network is trained on self-play games between different versions of Zahak. As of version 8, Zahak features an own network architecture which consists of 769 input features, that represents all the pieces on the board as well as a feature to represent white-to-move. The training process is thoroughly documented<ref>[https://github.com/amanjpro/zahak/blob/master/training.md Training Documentation · amanjpro/zahak · GitHub]</ref>. As of the time of this writing, Zahak is the only [[NNUE]] engine that is written in [[Go]].
Zahak started its first debut in [[TCEC]] in Swiss 2 event of S21<ref>[https://wiki.chessdom.org/TCEC_Swiss_2 TCEC Swiss 2 Wiki]</ref>.
==Name==
Zahak (or Zahhak or Azhi Dahak) is an evil figure in Iranian/Kurdish/Perisan mythology, evident in ancient Iranian folklore as Azhi Dahāka, the name by which he also appears in the texts of the Avesta. Legend has it, that he had two giant snakes on his shoulders and he had to feed them two human brains on daily basis<ref>[https://en.wikipedia.org/wiki/Zahhak Zahhak · Wikipedia]</ref>.
=Features=
<ref>Features based on [https://github.com/amanjpro/zahak#implemented-features README.md · amanjpro/zahak · GitHub]</ref>
==[[Board Representation]]==
* [[Bitboards]]
* [[Magic Bitboards]] for sliding pieces.
* Multi-Stage Pseudo-Legal [[Move Generation]]
==[[Search]]==
* [[Iterative Deepening]]
* [[Aspiration Windows]]
* [[Lazy SMP]]
* [[Principal Variation Search]]
* [[Transposition Table]]
** [[Shared Hash Table]]
** [[Zobrist Hashing]]
* [[Move Ordering]]
** [[Hash Move]]
** [[Static Exchange Evaluation|SEE]] for [[Captures]]
** [[Killer Heuristic]]
** [[History Heuristic]]
** [[Countermove Heuristic]]
* [[Selectivity]]
** [[Check Extensions]]
** [[Null Move Pruning]]
** [[Futility Pruning]]
** [[Reverse Futility Pruning]]
** [[Delta Pruning]]
** [[Static Exchange Evaluation|SEE]] based Pruning
** [[Late Move Reductions]]
** [[Late Move Pruning]]
** [[Quiescence Search]]
==[[Evaluation]]==
* [[NNUE]] (>= Zahak 7)
==Misc==
* [[Syzygy Bases]]
=Forum Posts=
==2021==
* [http://talkchess.com/forum3/viewtopic.php?f=2&t=76855&sid=9c19c86d4a40d94c20f01f0dfb046304 Zahak's announcement] by [[Amanj Sherwany]], [[Computer Chess Forums|CCRL Discussion Board]], March 13, 2021
=References=
[[FILE:zahak_logo.jpeg|border|right|thumb| <center>Zahak's Logo - Designed by Nasrin Zaza [https://www.linkedin.com/in/nasrin-zaza]</center>]]
'''Zahak''',<br/>
a [[UCI]] compliant [[:Category:Open Source|open source chess engine]] by [[Amanj Sherwany]], written in [[Go]], licensed under the [[Massachusetts_Institute_of_Technology#License|MIT License]] and first released on [https://en.wikipedia.org/wiki/GitHub GitHub] in February 2021 <ref>[https://github.com/amanjpro/zahak/releases/tag/0.0.1 Release Zahak 0.0.1 · amanjpro/zahak · GitHub]</ref>.
Since version 7, Zahak's hand crafted [[Evaluation Function | evaluation function]] is replaced with an [[NNUE | NNUE style]] evaluation, which is trained by a from scratch written trainer, that is written in [[Go]] as well<ref>[https://github.com/amanjpro/zahak-trainer amanjpro/zahak-trainer · GitHub]</ref>. The network is trained on self-play games between different versions of Zahak. As of version 8, Zahak features an own network architecture which consists of 769 input features, that represents all the pieces on the board as well as a feature to represent white-to-move. The training process is thoroughly documented<ref>[https://github.com/amanjpro/zahak/blob/master/training.md Training Documentation · amanjpro/zahak · GitHub]</ref>. As of the time of this writing, Zahak is the only [[NNUE]] engine that is written in [[Go]].
Zahak started its first debut in [[TCEC]] in Swiss 2 event of S21<ref>[https://wiki.chessdom.org/TCEC_Swiss_2 TCEC Swiss 2 Wiki]</ref>.
==Name==
Zahak (or Zahhak or Azhi Dahak) is an evil figure in Iranian/Kurdish/Perisan mythology, evident in ancient Iranian folklore as Azhi Dahāka, the name by which he also appears in the texts of the Avesta. Legend has it, that he had two giant snakes on his shoulders and he had to feed them two human brains on daily basis<ref>[https://en.wikipedia.org/wiki/Zahhak Zahhak · Wikipedia]</ref>.
=Features=
<ref>Features based on [https://github.com/amanjpro/zahak#implemented-features README.md · amanjpro/zahak · GitHub]</ref>
==[[Board Representation]]==
* [[Bitboards]]
* [[Magic Bitboards]] for sliding pieces.
* Multi-Stage Pseudo-Legal [[Move Generation]]
==[[Search]]==
* [[Iterative Deepening]]
* [[Aspiration Windows]]
* [[Lazy SMP]]
* [[Principal Variation Search]]
* [[Transposition Table]]
** [[Shared Hash Table]]
** [[Zobrist Hashing]]
* [[Move Ordering]]
** [[Hash Move]]
** [[Static Exchange Evaluation|SEE]] for [[Captures]]
** [[Killer Heuristic]]
** [[History Heuristic]]
** [[Countermove Heuristic]]
* [[Selectivity]]
** [[Check Extensions]]
** [[Null Move Pruning]]
** [[Futility Pruning]]
** [[Reverse Futility Pruning]]
** [[Delta Pruning]]
** [[Static Exchange Evaluation|SEE]] based Pruning
** [[Late Move Reductions]]
** [[Late Move Pruning]]
** [[Quiescence Search]]
==[[Evaluation]]==
* [[NNUE]] (>= Zahak 7)
==Misc==
* [[Syzygy Bases]]
=Forum Posts=
==2021==
* [http://talkchess.com/forum3/viewtopic.php?f=2&t=76855&sid=9c19c86d4a40d94c20f01f0dfb046304 Zahak's announcement] by [[Amanj Sherwany]], [[Computer Chess Forums|CCRL Discussion Board]], March 13, 2021
=References=
