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Created page with "'''Home * Engines * Cyrus 68K''' FILE:Illustrerad Verldshistoria band I Ill 058.jpg|border|right|thumb|200px| [https://en.wikipedia.org/wiki/Cyrus_the_Gre..."
'''[[Main Page|Home]] * [[Engines]] * Cyrus 68K'''
[[FILE:Illustrerad Verldshistoria band I Ill 058.jpg|border|right|thumb|200px| [https://en.wikipedia.org/wiki/Cyrus_the_Great Cyrus the Great] <ref>Illustration from "[http://sv.wikisource.org/wiki/Illustrerad_Verldshistoria Illustrerad verldshistoria] utgifven av [http://sv.wikisource.org/wiki/F%C3%B6rfattare:Ernst_Wallis Ernst Wallis]. Volume I": Relief of Cyrus, 1875. [https://en.wikipedia.org/wiki/Cyrus_the_Great Cyrus the Great from Wikipedia], not to confused with his grandfather [https://en.wikipedia.org/wiki/Cyrus_I Cyrus I]</ref> ]]
'''Cyrus 68K''',<br/>
a chess program by [[Mark Taylor]] and advisor [[David Levy]] for the [[68000]] (68K) based family of [https://en.wikipedia.org/wiki/Microprocessor microprocessors]. Cyrus 68K, not to confused with [[Richard Lang|Richard Lang's]] earlier program [[Cyrus]], was written by Taylor from scratch in 1985. Richard Lang, like Mark Taylor affiliated with Levy's and [[Kevin O’Connell|O’Connell's]] company [[Intelligent Software]], already focused on [[Psion]] at that time, had abandoned Intelligent Software, and was about to work for [[Hegener & Glaser]] on [[Mephisto]].
=Photos & Games=
[[FILE:TaylorOConnellLevy1986.JPG|none|border|text-bottom|link=http://www.chesscomputeruk.com/html/chess_computers_-_the_uk_story.html]]
[[Mark Taylor]], [[Kevin O’Connell]] and [[David Levy]] with [[Cyrus 68K]] vs. [[Nona]], [[WCCC 1986]] <ref>[http://www.chesscomputeruk.com/html/chess_computers_-_the_uk_story.html Chess Computers - The UK Story] from [http://www.chesscomputeruk.com/index.html Chess Computer UK] by [[Mike Watters]]</ref> <ref>[https://www.game-ai-forum.org/icga-tournaments/round.php?tournament=62&round=5&id=7 Cologne 1986 - Chess - Round 5 - Game 7 (ICGA Tournaments)]</ref>
<pre>
[Event "5th World Computer Chess Championship"]
[Site "Cologne, Germany"]
[Date "1986.06.15"]
[Round "5"]
[White "Nona"]
[Black "Cyrus 68K"]
[Result "1-0"]
1.d4 e6 2.e4 d5 3.Nc3 Bb4 4.e5 Ne7 5.Bd2 Nf5 6.Nf3 Be7 7.Bd3 Nc6 8.Be3 Nxe3
9.fxe3 Nb4 10.Be2 c5 11.O-O Nc6 12.Na4 c4 13.Nc3 Kf8 14.e4 Ke8 15.Rf2 h6
16.exd5 exd5 17.Qd2 Bf5 18.Nd1 Nb4 19.Ne3 Be4 20.b3 cxb3 21.axb3 h5 22.Ng5
Bxg5 23.Qxb4 Qe7 24.Bb5+ Kf8 25.Qxe7+ Kxe7 26.Re1 Ke6 27.c4 Raf8 28.cxd5+
Bxd5 29.Nxd5 Kxd5 30.e6 Be7 31.Rxf7 Rxf7 32.exf7 Bb4 33.Rd1 Rf8 34.Be2 h4
35.Bc4+ Kd6 36.Rf1 Bc3
37.Rf4 Rh8 38.f8=Q+ 1-0
</pre>
=SEX=
Cyrus 68K was Intelligent Software's testbed for the [[SEX Algorithm]], to apply [[Extensions#FractionalExtensions|fractional extensions]] and [[Reductions|reductions]], most notably already a kind of [[Late Move Reductions|LMR]], considering forced [[Tactical Moves|tactical moves]] such as [[Check|checks]], [[Captures|captures]], [[Checkmate|mate threats]] determined by [[Mate at a Glance]], as well as [[Killer Move|killer moves]] and early [[Quiet Moves|non-tactical moves]] and from a evaluated and sorted [[Move List|move list]] with a lower [[Depth|depth]] decrement than later non-tactical siblings.
Excerpts from ''The [[SEX Algorithm]] in Computer Chess'' 1989 <ref>[[David Levy]], [[David Broughton]], [[Mark Taylor]] ('''1989'''). ''The SEX Algorithm in Computer Chess''. [[ICGA Journal|ICCA Journal]], Vol. 12, No. 1, pp. 10-21.</ref> :
Later we designed a [[68000]] program called '''Cyrus 68K''', written by one of us ([[Mark Taylor]]), which evaluated and sorted all the moves from a node being expanded: we used these evaluations to determine the SXDEC for moves that were non-tactical. An obvious way to accomplish this is to assign the "best" (i.e., highest-scoring) non-tactical move a low SXDEC and to determine the SXDEC values for its non-tactical siblings on the basis of the difference in score among them.
...
A second generation of the search extension algorithm was developed during the period 1985-1988. Many of the original ideas were used but we tried to eliminate certain obvious deficiencies and to make the intelligence in the program more sophisticated. We came up with a number of new ideas and tested them in a [[68000]]-based program called '''Cyrus 68K'''. In general the results were rather encouraging, and we now feel that there is no longer a need to be shy about our work, hence the revised acronym for the algorithm and the renaming of the key variables to SEX and SEXDEC.
=The Sphinx=
Cyrus 68K was commercially available as the [[CXG Sphinx|Sphinx]], a [[Dedicated Chess Computers|dedicated chess computer]] under the brand name [[Newcrest Technology#CXG|CGX]], and manufactured by [[Eric White|Eric White's]] [[Newcrest Technology|Newcrest Technology Ltd.]], [https://en.wikipedia.org/wiki/Hong_Kong Hong Kong] <ref>[http://www.spacious-mind.com/html/cxg.html CXG Electronic Chess Computers] from [[The Spacious Mind]]</ref> <ref>[http://www.schach-computer.info/wiki/index.php/CXG CXG] from [http://www.schach-computer.info/wiki/index.php/Hauptseite_En Schachcomputer.info Wiki]</ref>.
=See also=
* [[CXG Sphinx]]
* [[Cyrus]]
=Publications=
* [[David Levy]], [[David Broughton]], [[Mark Taylor]] ('''1989'''). ''The SEX Algorithm in Computer Chess''. [[ICGA Journal|ICCA Journal]], Vol. 12, No. 1, pp. 10-21
=External Links=
==Chess Program==
* [https://www.game-ai-forum.org/icga-tournaments/program.php?id=405 Cyrus 68K' ICGA Tournaments]
* [http://www.chessgames.com/perl/chessplayer?pid=33964 The chess games of Cyrus 68K (Computer)] from [http://www.chessgames.com/index.html chessgames.com]
* [http://www.spacious-mind.com/html/cxg.html CXG Electronic Chess Computers] from [[The Spacious Mind]]
* [http://www.chesscomputeruk.com/html/chess_computers_-_the_uk_story.html Chess Computers - The UK Story] from [http://www.chesscomputeruk.com/index.html Chess Computer UK] by [[Mike Watters]]
==Misc==
* [https://en.wikipedia.org/wiki/Cyrus_(disambiguation) Cyrus (disambiguation) from Wikipedia]
* [https://en.wikipedia.org/wiki/Cyrus_I Cyrus I from Wikipedia]
* [https://en.wikipedia.org/wiki/Cyrus_the_Great Cyrus the Great from Wikipedia]
* [https://en.wikipedia.org/wiki/Cyrus_IMAP_server Cyrus IMAP server from Wikipedia]
=References=
<references />
'''[[Engines|Up one level]]'''
[[Category:Legend]]
[[FILE:Illustrerad Verldshistoria band I Ill 058.jpg|border|right|thumb|200px| [https://en.wikipedia.org/wiki/Cyrus_the_Great Cyrus the Great] <ref>Illustration from "[http://sv.wikisource.org/wiki/Illustrerad_Verldshistoria Illustrerad verldshistoria] utgifven av [http://sv.wikisource.org/wiki/F%C3%B6rfattare:Ernst_Wallis Ernst Wallis]. Volume I": Relief of Cyrus, 1875. [https://en.wikipedia.org/wiki/Cyrus_the_Great Cyrus the Great from Wikipedia], not to confused with his grandfather [https://en.wikipedia.org/wiki/Cyrus_I Cyrus I]</ref> ]]
'''Cyrus 68K''',<br/>
a chess program by [[Mark Taylor]] and advisor [[David Levy]] for the [[68000]] (68K) based family of [https://en.wikipedia.org/wiki/Microprocessor microprocessors]. Cyrus 68K, not to confused with [[Richard Lang|Richard Lang's]] earlier program [[Cyrus]], was written by Taylor from scratch in 1985. Richard Lang, like Mark Taylor affiliated with Levy's and [[Kevin O’Connell|O’Connell's]] company [[Intelligent Software]], already focused on [[Psion]] at that time, had abandoned Intelligent Software, and was about to work for [[Hegener & Glaser]] on [[Mephisto]].
=Photos & Games=
[[FILE:TaylorOConnellLevy1986.JPG|none|border|text-bottom|link=http://www.chesscomputeruk.com/html/chess_computers_-_the_uk_story.html]]
[[Mark Taylor]], [[Kevin O’Connell]] and [[David Levy]] with [[Cyrus 68K]] vs. [[Nona]], [[WCCC 1986]] <ref>[http://www.chesscomputeruk.com/html/chess_computers_-_the_uk_story.html Chess Computers - The UK Story] from [http://www.chesscomputeruk.com/index.html Chess Computer UK] by [[Mike Watters]]</ref> <ref>[https://www.game-ai-forum.org/icga-tournaments/round.php?tournament=62&round=5&id=7 Cologne 1986 - Chess - Round 5 - Game 7 (ICGA Tournaments)]</ref>
<pre>
[Event "5th World Computer Chess Championship"]
[Site "Cologne, Germany"]
[Date "1986.06.15"]
[Round "5"]
[White "Nona"]
[Black "Cyrus 68K"]
[Result "1-0"]
1.d4 e6 2.e4 d5 3.Nc3 Bb4 4.e5 Ne7 5.Bd2 Nf5 6.Nf3 Be7 7.Bd3 Nc6 8.Be3 Nxe3
9.fxe3 Nb4 10.Be2 c5 11.O-O Nc6 12.Na4 c4 13.Nc3 Kf8 14.e4 Ke8 15.Rf2 h6
16.exd5 exd5 17.Qd2 Bf5 18.Nd1 Nb4 19.Ne3 Be4 20.b3 cxb3 21.axb3 h5 22.Ng5
Bxg5 23.Qxb4 Qe7 24.Bb5+ Kf8 25.Qxe7+ Kxe7 26.Re1 Ke6 27.c4 Raf8 28.cxd5+
Bxd5 29.Nxd5 Kxd5 30.e6 Be7 31.Rxf7 Rxf7 32.exf7 Bb4 33.Rd1 Rf8 34.Be2 h4
35.Bc4+ Kd6 36.Rf1 Bc3
37.Rf4 Rh8 38.f8=Q+ 1-0
</pre>
=SEX=
Cyrus 68K was Intelligent Software's testbed for the [[SEX Algorithm]], to apply [[Extensions#FractionalExtensions|fractional extensions]] and [[Reductions|reductions]], most notably already a kind of [[Late Move Reductions|LMR]], considering forced [[Tactical Moves|tactical moves]] such as [[Check|checks]], [[Captures|captures]], [[Checkmate|mate threats]] determined by [[Mate at a Glance]], as well as [[Killer Move|killer moves]] and early [[Quiet Moves|non-tactical moves]] and from a evaluated and sorted [[Move List|move list]] with a lower [[Depth|depth]] decrement than later non-tactical siblings.
Excerpts from ''The [[SEX Algorithm]] in Computer Chess'' 1989 <ref>[[David Levy]], [[David Broughton]], [[Mark Taylor]] ('''1989'''). ''The SEX Algorithm in Computer Chess''. [[ICGA Journal|ICCA Journal]], Vol. 12, No. 1, pp. 10-21.</ref> :
Later we designed a [[68000]] program called '''Cyrus 68K''', written by one of us ([[Mark Taylor]]), which evaluated and sorted all the moves from a node being expanded: we used these evaluations to determine the SXDEC for moves that were non-tactical. An obvious way to accomplish this is to assign the "best" (i.e., highest-scoring) non-tactical move a low SXDEC and to determine the SXDEC values for its non-tactical siblings on the basis of the difference in score among them.
...
A second generation of the search extension algorithm was developed during the period 1985-1988. Many of the original ideas were used but we tried to eliminate certain obvious deficiencies and to make the intelligence in the program more sophisticated. We came up with a number of new ideas and tested them in a [[68000]]-based program called '''Cyrus 68K'''. In general the results were rather encouraging, and we now feel that there is no longer a need to be shy about our work, hence the revised acronym for the algorithm and the renaming of the key variables to SEX and SEXDEC.
=The Sphinx=
Cyrus 68K was commercially available as the [[CXG Sphinx|Sphinx]], a [[Dedicated Chess Computers|dedicated chess computer]] under the brand name [[Newcrest Technology#CXG|CGX]], and manufactured by [[Eric White|Eric White's]] [[Newcrest Technology|Newcrest Technology Ltd.]], [https://en.wikipedia.org/wiki/Hong_Kong Hong Kong] <ref>[http://www.spacious-mind.com/html/cxg.html CXG Electronic Chess Computers] from [[The Spacious Mind]]</ref> <ref>[http://www.schach-computer.info/wiki/index.php/CXG CXG] from [http://www.schach-computer.info/wiki/index.php/Hauptseite_En Schachcomputer.info Wiki]</ref>.
=See also=
* [[CXG Sphinx]]
* [[Cyrus]]
=Publications=
* [[David Levy]], [[David Broughton]], [[Mark Taylor]] ('''1989'''). ''The SEX Algorithm in Computer Chess''. [[ICGA Journal|ICCA Journal]], Vol. 12, No. 1, pp. 10-21
=External Links=
==Chess Program==
* [https://www.game-ai-forum.org/icga-tournaments/program.php?id=405 Cyrus 68K' ICGA Tournaments]
* [http://www.chessgames.com/perl/chessplayer?pid=33964 The chess games of Cyrus 68K (Computer)] from [http://www.chessgames.com/index.html chessgames.com]
* [http://www.spacious-mind.com/html/cxg.html CXG Electronic Chess Computers] from [[The Spacious Mind]]
* [http://www.chesscomputeruk.com/html/chess_computers_-_the_uk_story.html Chess Computers - The UK Story] from [http://www.chesscomputeruk.com/index.html Chess Computer UK] by [[Mike Watters]]
==Misc==
* [https://en.wikipedia.org/wiki/Cyrus_(disambiguation) Cyrus (disambiguation) from Wikipedia]
* [https://en.wikipedia.org/wiki/Cyrus_I Cyrus I from Wikipedia]
* [https://en.wikipedia.org/wiki/Cyrus_the_Great Cyrus the Great from Wikipedia]
* [https://en.wikipedia.org/wiki/Cyrus_IMAP_server Cyrus IMAP server from Wikipedia]
=References=
<references />
'''[[Engines|Up one level]]'''
[[Category:Legend]]
