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| rowspan="2" | '''Arasan''',<br/>
an [[:Category:Open Source|open source engine]] written by [[Jon Dart]] in [[Cpp|C++]]. Arasan's development started in the early 90s, the first version, released in 1994 was a 16-bit program running under [[Windows|Windows 3.1]] using an [[8x8 Board]], [[Incremental Updates|incremental updated]] [[Attack and Defend Maps|attack tables]] and its own [[GUI]], evolving to a portable 32-bit and later 64-bit program, utilizing [[Bitboards|bitboards]] to determine its [[Sliding Piece Attacks|sliding piece attacks]] with [[Rotated Bitboards|rotated bitboard lookups]]. In 2008, rotated were replaced by [[Magic Bitboards|Magic bitboards]], which gave Arasan about a 20-25% speedup <ref>[httphttps://www.arasanchess.org/blogs/aug08.html Arasan Blog - Aug 26, 2008]</ref>.
Despite its own GUI, Arasan early supported the [[Chess Engine Communication Protocol]] and later [[UCI]] as well, to run under [[Windows]], [[Linux]] and [[Mac OS]] <ref>[httphttps://www.arasanchess.org/ Arasan chess]</ref>. The latest version of Arasan and all major versions, including Version 1.0 from March 1994, are available as source code from the Arasan.org site <ref>[httphttps://www.arasanchess.org/downld.shtml Arasan Downloads]</ref> . Jon's change logs, bug fix reports and tournament reports over the time are available from [[Computer Chess Forums|forum archives]], as well the recent ones from the Arasan blog <ref>[httphttps://arasanchess.org/blog.shtml Arasan Tech Blog]</ref>
| <span style="font-size: 600%;">அரசன்</span>
=Magic Bitboards=
[[Jon Dart]], August 2008 <ref>[httphttps://www.arasanchess.org/blogs/aug08.html Arasan Blog - Aug 26, 2008]</ref> :
The main change has been to re-work the code to use [[Magic Bitboards|"magic" bitboard logic]] instead of [[Rotated Bitboards|rotated bitboards]]. This has given about a 20-25% speedup. I have also had to re-write the [[Evaluation|evaluation function]] to take advantage of bitboard attack functions for [[King Safety|king safety]] and [[Mobility|mobility]].
=External Links=
==Chess Engine==
* [httphttps://arasanchess.org/index.shtml Arasan Chess] by [[Jon Dart]]
* [https://arasanchess.org/programr.shtml Arasan Programmer's Guide] by [[Jon Dart]] <ref>[http://www.talkchess.com/forum/viewtopic.php?t=64364 Arasan Programmer's Guide] by [[Jon Dart]], [[CCC]], June 21, 2017</ref>
* [httphttps://www.arasanchess.org/testsuite.shtml Arasan Test Suite]
* [http://www.playwitharena.com/?Newsticker:Archive_5 Arasan 8.4 released, short interview with Jon Dart] by [[Frank Quisinsky]], March 01, 2005, [[Arena|Arena Chess GUI]], Archive 5, 72
* [https://github.com/jdart1/arasan-chess jdart1/arasan-chess · GitHub] <ref>[http://www.talkchess.com/forum/viewtopic.php?t=48082 Arasan on github] by [[Jon Dart]], [[CCC]], May 22, 2013</ref>
