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Created page with "'''Home * Engines * Usurpator''' FILE:usurbook.jpg|border|right|thumb|280px|link=http://home.hccnet.nl/h.g.muller/chess.html| Usurpator <ref>[http://home...."
'''[[Main Page|Home]] * [[Engines]] * Usurpator'''
[[FILE:usurbook.jpg|border|right|thumb|280px|link=http://home.hccnet.nl/h.g.muller/chess.html| Usurpator <ref>[http://home.hccnet.nl/h.g.muller/chess.html HGM's Chess Pages]</ref> ]]
'''Usurpator''',<br/>
a series of microcomputer chess programs by [[Harm Geert Muller]] (HGM), written in [[Assembly|assembly]] for [[6800]] (Usurpator I) and [[6502]] (Usurpator II), published with listings as a regular book <ref>[[Harm Geert Muller]] ('''1981'''). ''Usurpator 6502 6800 computerschaak''. Wolfkamp</ref>, also adapted for the [[Acorn Atom]] <ref>[http://stardot.org.uk/forums/viewtopic.php?t=6544&start=900#p124794 Re: Atom Software Archive] by Multiwizard, [http://stardot.org.uk/forums/index.php stardot.org.uk], November 13, 2015</ref> <ref>[http://www.acornatom.nl/atom_nieuws/1982/nr4/19824015.htm Acorn Nieuws 1982 nummer 4]</ref> . Usurpator participated at eight [[Dutch Open Computer Chess Championship|Dutch Computer Chess Championships]], with some gaps seven times in the period from [[DOCCC 1981|1981]] until the [[DOCCC 1990|10th DOCCC]], where Usurpator competed as matchbox computer <ref>[http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=126155&t=14610 Re: Retrocomputing with the 6502] by [[Harm Geert Muller]], [[Computer Chess Forums|CCC]], June 22, 2007</ref> .
In 2005, 15 years later, Harm Geert Muller was invited by the [[CSVN]] to play the [[DOCCC 2005|25th DOCCC]], and he rewrote Usurpator in [[C]] (Usurpator V), to run on a laptop, which was 10,000 times faster and had 100,000 times as much memory as the matchbox computer. Since the program was not designed to play that fast, it was thinking much too far ahead at the expense of immediate threats.
=Matchbox=
HGM's matchbox computer with a [http://www.baltissen.org/newhtm/65sc816.htm 65SC816] CPU for the purpose of running Usurpator. The matchbox competed three times at [[Dutch Open Computer Chess Championship|Dutch Computer Chess Championships]], [[DOCCC 1986|1986]] <ref>[[Jaap van Oosterwijk Bruyn]] ('''1986'''). ''Nona retains her Title''. [[ICGA Journal#9_3|ICCA Journal, Vol. 9, No. 3]]</ref> , [[DOCCC 1987|1987]] <ref>[[Peter Kouwenhoven]] ('''1987'''). ''The 7th Dutch National Computer-Chess Championship''. [[ICGA Journal#10_4|ICCA Journal, Vol. 10, No. 4]]</ref> , and [[DOCCC 1990|1990]]:
{|
|-
| [[FILE:HGMwithMatchbox.jpg|none|border|text-bottom|280px|link=http://tinyurl.com/h7yzxry]]
| [[FILE:HGMmatchbox.jpg|none|border|text-bottom|link=http://home.hccnet.nl/h.g.muller/chess.html]]
|-
| [[DOCCC 1990]] - Firepower for a full board <ref>Image by [[Jos Uiterwijk]], from [[Harm Geert Muller]] ('''1990'''). ''A Matchbox Chess Computer''. [[ICGA Journal#13_4|ICCA Journal, Vol. 13, No. 4]], [http://tinyurl.com/h7yzxry pdf] hosted by [[Hein Veldhuis]]</ref>
| Matchbox Design <ref>[http://home.hccnet.nl/h.g.muller/chess.html HGM's Chess Pages]</ref>
|}
=Re-Discovering Alpha-Beta=
In that early times end of the 70s and early 80s when Harm Geert Muller developed his first programs, he had [[Alpha-Beta]] initially wrong in Usurpator I, since it omitted the [[Beta-Cutoff#deep|deep cutoffs]] and was not passing [[Alpha|alpha]] through the [[Recursion|recursive]] call. After tracing the [[Search Tree|search tree]] HGM got aware and found out how to do the deep cutoffs, re-discovering Alpha-Beta by himself for Usurpator II <ref>[http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=394125&t=38007 Re: What the computer chess community needs to decide] by [[Harm Geert Muller]], [[Computer Chess Forums|CCC]], February 11, 2011</ref> .
=Photos & Games=
[[FILE:MulArts42a.JPG|none|border|text-bottom|640px|link=http://old.csvn.nl/gallery23.html]]
[[DOCCC 2005]]: [[Harm Geert Muller]] and [[Stan Arts]], [[Usurpator|Usurpator V]] - [[Neurosis]] <ref>[http://old.csvn.nl/gallery23.html 25th Dutch Open Computer Chess Championship 2005 - Photo Gallery]</ref> <ref>[http://www.csvn.nl/index.php?option=com_docman&task=cat_view&gid=37&Itemid=26&lang=en&limitstart=5 Downloads | Open Dutch Computer Chess Championships | Games]</ref><br/>Usurpator V caused some thermic problems in the therefor upright standing Laptop
<pre>
[Event "DOCCC 2005"]
[Site "Leiden NED"]
[Date "2005.11.11"]
[Round "02"]
[White "Usurpator V"]
[Black "Neurosis"]
[Result "0-1"]
1.e4 e5 2.Qh5 Nc6 3.Bc4 g6 4.Qe2 Nd4 5.Qd3 Nf6 6.c3 Nc6 7.Nf3 Bg7
8.b4 d5 9.Bxd5 Nxd5 10.exd5 Be6 11.h3 Bxd5 12.Qc2 e4 13.Ng1 Qg5
14.g4 e3 15.Rh2 Qf4 16.Rg2 Bxg2 17.dxe3 Qh2 18.Ne2 Qh1+ 19.Kd2 O-O-O+
20.Nd4 Ne5 21.Qa4 Nc4+ 22.Kc2 Be4+ 23.Kb3 Qd1+ 24.Kxc4 Bd3+
25.Kc5 Bf8# 0-1
</pre>
=See also=
* [[KingSlayer]]
* [[Micro-Max]]
* [[Spartacus]]
=Publications=
* [[Harm Geert Muller]] ('''1981'''). ''Usurpator 6502 6800 computerschaak''. Wolfkamp
* [[Harm Geert Muller]] ('''1990'''). ''A Matchbox Chess Computer''. [[ICGA Journal#13_4|ICCA Journal, Vol. 13, No. 4]], [http://tinyurl.com/h7yzxry pdf] hosted by [[Hein Veldhuis]]
=Forum Posts=
* [http://www.talkchess.com/forum/viewtopic.php?t=64747 UsurpatorII emu questions] by [[Günther Simon]], [[CCC]], July 28, 2017
=External Links=
==Chess Program==
* [http://home.hccnet.nl/h.g.muller/chess.html HGM's Chess Pages]
* [http://adamsccpages.blogspot.com/2012/06/hgm-and-matchbox-chess-computer.html HGM and The Matchbox Chess Computer] from [http://adamsccpages.blogspot.com/ Adam's Computer Chess Pages] by [[Adam Hair]], June 1, 2012
==Misc==
* [https://en.wikipedia.org/wiki/Usurper Usurper from Wikipedia]
* [https://en.wikipedia.org/wiki/Roman_usurper Roman usurper from Wikipedia]
* [https://en.wikipedia.org/wiki/List_of_usurpers List of usurpers from Wikipedia]
* [https://en.wikipedia.org/wiki/List_of_Roman_usurpers List of Roman usurpers from Wikipedia]
* [https://en.wikipedia.org/wiki/Usurper_%28game%29 Usurper (video game) from Wikipedia]
=References=
<references />
'''[[Engines|Up one Level]]'''
[[FILE:usurbook.jpg|border|right|thumb|280px|link=http://home.hccnet.nl/h.g.muller/chess.html| Usurpator <ref>[http://home.hccnet.nl/h.g.muller/chess.html HGM's Chess Pages]</ref> ]]
'''Usurpator''',<br/>
a series of microcomputer chess programs by [[Harm Geert Muller]] (HGM), written in [[Assembly|assembly]] for [[6800]] (Usurpator I) and [[6502]] (Usurpator II), published with listings as a regular book <ref>[[Harm Geert Muller]] ('''1981'''). ''Usurpator 6502 6800 computerschaak''. Wolfkamp</ref>, also adapted for the [[Acorn Atom]] <ref>[http://stardot.org.uk/forums/viewtopic.php?t=6544&start=900#p124794 Re: Atom Software Archive] by Multiwizard, [http://stardot.org.uk/forums/index.php stardot.org.uk], November 13, 2015</ref> <ref>[http://www.acornatom.nl/atom_nieuws/1982/nr4/19824015.htm Acorn Nieuws 1982 nummer 4]</ref> . Usurpator participated at eight [[Dutch Open Computer Chess Championship|Dutch Computer Chess Championships]], with some gaps seven times in the period from [[DOCCC 1981|1981]] until the [[DOCCC 1990|10th DOCCC]], where Usurpator competed as matchbox computer <ref>[http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=126155&t=14610 Re: Retrocomputing with the 6502] by [[Harm Geert Muller]], [[Computer Chess Forums|CCC]], June 22, 2007</ref> .
In 2005, 15 years later, Harm Geert Muller was invited by the [[CSVN]] to play the [[DOCCC 2005|25th DOCCC]], and he rewrote Usurpator in [[C]] (Usurpator V), to run on a laptop, which was 10,000 times faster and had 100,000 times as much memory as the matchbox computer. Since the program was not designed to play that fast, it was thinking much too far ahead at the expense of immediate threats.
=Matchbox=
HGM's matchbox computer with a [http://www.baltissen.org/newhtm/65sc816.htm 65SC816] CPU for the purpose of running Usurpator. The matchbox competed three times at [[Dutch Open Computer Chess Championship|Dutch Computer Chess Championships]], [[DOCCC 1986|1986]] <ref>[[Jaap van Oosterwijk Bruyn]] ('''1986'''). ''Nona retains her Title''. [[ICGA Journal#9_3|ICCA Journal, Vol. 9, No. 3]]</ref> , [[DOCCC 1987|1987]] <ref>[[Peter Kouwenhoven]] ('''1987'''). ''The 7th Dutch National Computer-Chess Championship''. [[ICGA Journal#10_4|ICCA Journal, Vol. 10, No. 4]]</ref> , and [[DOCCC 1990|1990]]:
{|
|-
| [[FILE:HGMwithMatchbox.jpg|none|border|text-bottom|280px|link=http://tinyurl.com/h7yzxry]]
| [[FILE:HGMmatchbox.jpg|none|border|text-bottom|link=http://home.hccnet.nl/h.g.muller/chess.html]]
|-
| [[DOCCC 1990]] - Firepower for a full board <ref>Image by [[Jos Uiterwijk]], from [[Harm Geert Muller]] ('''1990'''). ''A Matchbox Chess Computer''. [[ICGA Journal#13_4|ICCA Journal, Vol. 13, No. 4]], [http://tinyurl.com/h7yzxry pdf] hosted by [[Hein Veldhuis]]</ref>
| Matchbox Design <ref>[http://home.hccnet.nl/h.g.muller/chess.html HGM's Chess Pages]</ref>
|}
=Re-Discovering Alpha-Beta=
In that early times end of the 70s and early 80s when Harm Geert Muller developed his first programs, he had [[Alpha-Beta]] initially wrong in Usurpator I, since it omitted the [[Beta-Cutoff#deep|deep cutoffs]] and was not passing [[Alpha|alpha]] through the [[Recursion|recursive]] call. After tracing the [[Search Tree|search tree]] HGM got aware and found out how to do the deep cutoffs, re-discovering Alpha-Beta by himself for Usurpator II <ref>[http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=394125&t=38007 Re: What the computer chess community needs to decide] by [[Harm Geert Muller]], [[Computer Chess Forums|CCC]], February 11, 2011</ref> .
=Photos & Games=
[[FILE:MulArts42a.JPG|none|border|text-bottom|640px|link=http://old.csvn.nl/gallery23.html]]
[[DOCCC 2005]]: [[Harm Geert Muller]] and [[Stan Arts]], [[Usurpator|Usurpator V]] - [[Neurosis]] <ref>[http://old.csvn.nl/gallery23.html 25th Dutch Open Computer Chess Championship 2005 - Photo Gallery]</ref> <ref>[http://www.csvn.nl/index.php?option=com_docman&task=cat_view&gid=37&Itemid=26&lang=en&limitstart=5 Downloads | Open Dutch Computer Chess Championships | Games]</ref><br/>Usurpator V caused some thermic problems in the therefor upright standing Laptop
<pre>
[Event "DOCCC 2005"]
[Site "Leiden NED"]
[Date "2005.11.11"]
[Round "02"]
[White "Usurpator V"]
[Black "Neurosis"]
[Result "0-1"]
1.e4 e5 2.Qh5 Nc6 3.Bc4 g6 4.Qe2 Nd4 5.Qd3 Nf6 6.c3 Nc6 7.Nf3 Bg7
8.b4 d5 9.Bxd5 Nxd5 10.exd5 Be6 11.h3 Bxd5 12.Qc2 e4 13.Ng1 Qg5
14.g4 e3 15.Rh2 Qf4 16.Rg2 Bxg2 17.dxe3 Qh2 18.Ne2 Qh1+ 19.Kd2 O-O-O+
20.Nd4 Ne5 21.Qa4 Nc4+ 22.Kc2 Be4+ 23.Kb3 Qd1+ 24.Kxc4 Bd3+
25.Kc5 Bf8# 0-1
</pre>
=See also=
* [[KingSlayer]]
* [[Micro-Max]]
* [[Spartacus]]
=Publications=
* [[Harm Geert Muller]] ('''1981'''). ''Usurpator 6502 6800 computerschaak''. Wolfkamp
* [[Harm Geert Muller]] ('''1990'''). ''A Matchbox Chess Computer''. [[ICGA Journal#13_4|ICCA Journal, Vol. 13, No. 4]], [http://tinyurl.com/h7yzxry pdf] hosted by [[Hein Veldhuis]]
=Forum Posts=
* [http://www.talkchess.com/forum/viewtopic.php?t=64747 UsurpatorII emu questions] by [[Günther Simon]], [[CCC]], July 28, 2017
=External Links=
==Chess Program==
* [http://home.hccnet.nl/h.g.muller/chess.html HGM's Chess Pages]
* [http://adamsccpages.blogspot.com/2012/06/hgm-and-matchbox-chess-computer.html HGM and The Matchbox Chess Computer] from [http://adamsccpages.blogspot.com/ Adam's Computer Chess Pages] by [[Adam Hair]], June 1, 2012
==Misc==
* [https://en.wikipedia.org/wiki/Usurper Usurper from Wikipedia]
* [https://en.wikipedia.org/wiki/Roman_usurper Roman usurper from Wikipedia]
* [https://en.wikipedia.org/wiki/List_of_usurpers List of usurpers from Wikipedia]
* [https://en.wikipedia.org/wiki/List_of_Roman_usurpers List of Roman usurpers from Wikipedia]
* [https://en.wikipedia.org/wiki/Usurper_%28game%29 Usurper (video game) from Wikipedia]
=References=
<references />
'''[[Engines|Up one Level]]'''
