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Created page with "'''Home * Engines * Nimzo''' FILE:Aron Nimzowitsch.jpg|border|right|thumb|Aron Nimzowitsch <ref>[https://en.wikipedia.org/wiki/Aron_Nimzowitsch Aron Nimzo..."
'''[[Main Page|Home]] * [[Engines]] * Nimzo'''
[[FILE:Aron Nimzowitsch.jpg|border|right|thumb|Aron Nimzowitsch <ref>[https://en.wikipedia.org/wiki/Aron_Nimzowitsch Aron Nimzowitsch from Wikipedia]</ref> ]]
'''Nimzo''',<br/>
a chess program by primary developer [[Chrilly Donninger]], subsequently supported by members of the [[First Vienna Computer Chess Club]] (Nimzo Werkstatt) concerning [[Engine Testing|testing]], [[Knowledge|chess knowledge]], [[Opening Book|opening book]] and hardware. The program was first dubbed ''Nimzo-Guernica'' in remembrance to [https://en.wikipedia.org/wiki/Aron_Nimzowitsch Aron Nimzowitsch] and as manifest of Chrilly's [https://en.wikipedia.org/wiki/Anti-war Anti-war] engagement <ref>[https://en.wikipedia.org/wiki/Bombing_of_Guernica Bombing of Guernica from Wikiepedia]</ref>. It had its tournament debut at the [[3rd Computer Olympiad#Chess|3rd Computer Olympiad 1991]] and further played the [[DOCCC 1991]] and [[IPCCC 1991]]. At the [[WMCCC 1993]], Nimzo-Guernica aka Nimzo-2 upset [[Gideon|Mephisto Gideon]] <ref>With the help of a sign bug in [[Passed Pawn|passed pawn]] evaluation, see [[Chrilly Donninger]] ('''1999'''). ''Computer machen keine Fehler''. [[Computerschach und Spiele|CSS]] 2/99, [http://www.mustrum.de/chrilly/keine_fehler.pdf pdf] (German)</ref> and later winner [[Hiarcs]] to lead the pack after five rounds, and finished strong fourth despite 1.5 points out of the last four rounds.
=Photos & Games=
[[FILE:bronsteinchrillyjohan.gif|none|border|text-bottom|638px|link=http://www.thorstenczub.de/aegon.html]]
[[David Bronstein]] playing Nimzo by [[Chrilly Donninger]], [[Johan de Koning]] kibitzing, [[Aegon 1997]] <ref>[[David Bronstein]] vs. [[Nimzo]], Photo by [[Thorsten Czub]] from [http://www.thorstenczub.de/aegon.html Aegon 1996-97]</ref>
<pre>
[Event "AEGON 1997"]
[Site "The Hague NED"]
[Date "1997.04.17"]
[Round "02"]
[White "David Bronstein"]
[Black "NIMZO"]
[Result "0-1"]
1.e4 c5 2.Nf3 d6 3.c3 Nf6 4.Bd3 Bg4 5.h3 Bxf3 6.Qxf3 Nc6 7.O-O g6 8.Bb5 Bg7 9.e5 dxe5
10.Bxc6+ bxc6 11.Qxc6+ Nd7 12.d3 O-O 13.Nd2 Rc8 14.Qa6 Qb6 15.Qa4 Rfd8 16.Nb3 Nf6
17.Qc4 Ne8 18.Bg5 Nd6 19.Qa4 Bf6 20.Be3 Nf5 21.Qc4 Nxe3 22.fxe3 a5 23.Rad1 a4 24.Nd2
Qxb2 25.Ne4 Qe2 26.Rfe1 Qh5 27.Rd2 Bg5 28.Rf2 e6 29.Rf3 Qh6 30.Kh1 Be7 31.Ref1 Qg7
32.g4 a3 33.g5 Rd5 34.h4 Rcd8 35.Nf2 h5 36.e4 R5d7 37.Qa6 Qf8 38.Nd1 Qe8 39.Kg2 Bf8
40.R1f2 Rd6 41.Qc4 R6d7 42.Rd2 Rb7 43.Kf1 Rdb8 44.Ke2 Ra7 45.d4 Ra4 46.Qd3 cxd4
47.c4 Qc6 48.Rc2 Rbb4 49.c5 Ra5 50.Nf2 Rxc5 51.Rxc5 Rb2+ 52.Kf1 Qxc5 53.Qa6 Rxa2
54.Qa7 f6 55.gxf6 Rb2 56.Qa8 Qc1+ 57.Kg2 a2 58.Qe8 a1=Q 59.Qxg6+ Kh8 60.Qxh5+ Qh6
61.Qf7 Qd1 62.Rg3 Rxf2+ 63.Kxf2 Qhd2#
0-1
</pre>
=Nimzo-3=
Guernica and Nimzo-2 were leaf evaluators to spent 60 to 70 percent of its time in [[Evaluation|evaluation]]. The main design criterion for Nimzo-3 was combining the positional play of Nimzo-2 with the [[Tactics|tactical]] strength of a program like [[Fritz]]. Nimzo-3 therefor became a [[Chess Genius|Genius]]/Fritz like program with a complex root evaluation <ref>[[Chrilly Donninger]] ('''1996'''). ''CHE: A Graphical Language for Expressing Chess Knowledge''. [[ICGA Journal#19_4|ICCA Journal, Vol. 19, No. 4]]</ref>, called [[Oracle]] as proposed by [[Hans Berliner]] <ref>[[Hans Berliner]] ('''1987'''). ''Some Innovations Introduced by Hitech''. [[ICGA Journal#10_3|ICCA Journal, Vol. 10, No. 3]]</ref> <ref>[[Hans Berliner]] ('''1989'''). ''Some Innovations Introduced by Hitech''. [[Advances in Computer Chess 5]]</ref>, and which seems to have been first used by [[Kaare Danielsen]]. The oracle approach with very simple, mainly first-order evaluation terms at the leaves, made Nimzo-3 to spent about only 10 to 20 percent on leaf evaluation, yielding in an increased node rate of 400%.
=CHE=
The [[CHE]] and CHE++ declarative language for expressing chess knowledge using a [[GUI]] was used to incorporate [[Planning |planning]] features within the oracle used <ref>[https://www.stmintz.com/ccc/index.php?id=198528 CHE docs in English / Nimzo 3 version] by Mike S., [[CCC]], November 22, 2001</ref>.
=Commerce=
During the [[WMCCC 1996]], Nimzo was still amateur, but soon went commercial as [[MS-DOS]] program Nimzo 3.5 and the [[Windows]] program Nimzo 2000 distributed by [[Ossi Weiner|Weiner's]] [[Millennium 2000 GmbH]], later released as [[Chess Engine Communication Protocol]] compliant engine WBNimzo. Nimzo98, Nimzo99 were native [[ChessBase]] engines, followed by Nimzo 7.32 and Nimzo 8 and its derivation [[Schweinehund]] <ref>[https://www.stmintz.com/ccc/index.php?id=144598 Re: Versions of Nimzo] by Shep, [[CCC]], December 12, 2000</ref> <ref>[https://www.stmintz.com/ccc/index.php?id=265975 Re: Nimzo 4] by [[Manfred Meiler]], [[CCC]], November 19, 2002</ref>.
=Description=
given in 1999 from the [[ICGA]] tournament site <ref>[https://www.game-ai-forum.org/icga-tournaments/program.php?id=93 Nimzo's ICGA Tournaments]</ref>:
Nimzo is one of the leading professional chess programs. It combines sound positional play with extremely strong tactics. Nimzo-Paderborn is a considerable improved version of the currently commercially available programs Nimzo98, Nimzo99 and Nimzo2000.
Nimzo-Paderborn [[Learning|learns]] automatically from human grandmaster games. It is also equipped with an own Chess-Advice-Language (Che++) which allows strong human players to formulate chess-knowledge. The program can also access in its search [[Endgame Tablebases|endgame databases]]. It therefore searches regularly from the middlegame into won endgames.
<span id="Pruning"></span>
=Forward Pruning in Nimzo 2.2.1=
Following [[Pruning|forward pruning]] code appears in Nimzo's 2.2.1 search routine <ref>Nimzo: sr.c: search-tree handling (dead acor link) hosted by Roger Thormann</ref> applied at [[Frontier Nodes|frontier nodes]], notably the aggressive [[Richard Lang|Lang]] mode at pre-pre-frontier nodes or below. The source was published along with a foreword by Donninger in 2002 <ref>home.arcor.de/roger.thormann/yacdb.com/nimzo/vorwort.html Vorwort von Chrilly Donninger (German) hosted by Roger Thormann</ref> :
<pre>
if((depth <= 1) && (!extflg) && (score > beta) && (GPtr->hung.w <= KNIGHTHUNG)) {
return score;
}
if(LangModus) {
if((depth <= 3) && (!extflg) && (score > beta) && (GPtr->hung.w == 0)) {
return score;
}
}
</pre>
=See also=
* [[Brutus]]
* [[Various Classifications#ChessLegend|Chess legends]]
* [[Hydra]]
* [[Hydra 97]]
* [[WMCCC 1993#NimzoBug|Nimzo's winning white-black bug]], [[WMCCC 1993]]
* [[Schweinehund]]
=Publications=
* [[Chrilly Donninger]] ('''1992'''). ''The Relation of Mobility, Strategy and the Mean Dead Rabbit in Chess''. Heuristic Programming in Artificial Intelligence 3: the third computer olympiad (eds. [[Jaap van den Herik]] and [[Victor Allis]]), pp. 102-111. Ellis Horwood Ltd., Chichester, UK. ISBN 0-13-388265-9
* [[Chrilly Donninger]] ('''1993'''). ''Null Move and Deep Search: Selective-Search Heuristics for Obtuse Chess Programs''. [[ICGA Journal#16_3|ICCA Journal, Vol. 16, No. 3]]
* [[Thomas Mally]] ('''1993'''). ''PC Power in Braille - Nimzo Guernica: Ein PC-Schachprogramm für Blinde''. [[PC Schach]] 3/93 (German) <ref>[https://en.wikipedia.org/wiki/Braille Braille from Wikipedia]</ref>
* [[Chrilly Donninger]] ('''1996'''). ''CHE: A Graphical Language for Expressing Chess Knowledge''. [[ICGA Journal#19_4|ICCA Journal, Vol. 19, No. 4]]
=Forum Posts=
* [https://groups.google.com/d/msg/rec.games.chess.computer/fON9kA5LPYo/Jpfn6nqs3yYJ NIMZO 3 ist out now!] by [[Tom Kerrigan]], [[Computer Chess Forums|rgcc]], July 15, 1996
: [https://groups.google.com/d/msg/rec.games.chess.computer/fON9kA5LPYo/_utfvtP6RzsJ Re: NIMZO 3 ist out now!] by [[Peter Schreiner]], [[Computer Chess Forums|rgcc]], July 19, 1996
* [https://groups.google.com/d/msg/rec.games.chess.computer/lZshGHUeuxY/Kfef3R7vIkQJ Re: Nimzo3 - playing strength?] by [[Helmut Weigel]], [[Computer Chess Forums|rgcc]], August 04, 1996
* [https://groups.google.com/d/msg/rec.games.chess.computer/o57y2Ldf-ks/rlfhb1TeyYMJ NIMZO 3 !] by Komputer Korner, [[Computer Chess Forums|rgcc]], December 01, 1996
* [http://groups.google.com/group/rec.games.chess.computer/msg/f9c5ab9792a46513 Re: computer chess "oracle" ideas...] by [[Andreas Mader]], reply to [[Ronald de Man]], [[Computer Chess Forums|rgcc]], April 7, 1997
* [http://groups.google.com/group/rec.games.chess.computer/msg/2a9279e002cfec4b Re: Any word on future Nimzo plans] by [[Andreas Mader]], [[Computer Chess Forums|rgcc]], March 22, 1998
* [https://www.stmintz.com/ccc/index.php?id=148289 Nimzo 8 and piece values] by Matthew Barnett, [[CCC]], January 05, 2001
* [http://www.talkchess.com/forum/viewtopic.php?t=60404 Nimzo Engines of Millenium Chess System] by [[Norbert Raimund Leisner]], [[CCC]], June 08, 2016
=External Links=
==Chess Engine==
* [https://www.game-ai-forum.org/icga-tournaments/program.php?id=93 Nimzo's ICGA Tournaments]
==Misc==
* [https://en.wikipedia.org/wiki/Aron_Nimzowitsch Aron Nimzowitsch from Wikipedia]
* [https://en.wikipedia.org/wiki/Guernica_%28town%29 Guernica (town) from Wikipedia]
* [https://en.wikipedia.org/wiki/Bombing_of_Guernica Bombing of Guernica from Wikiepedia]
* [https://en.wikipedia.org/wiki/Guernica_%28painting%29 Guernica (painting) from Wikipedia]
=References=
<references />
'''[[Engines|Up one Level]]'''
[[FILE:Aron Nimzowitsch.jpg|border|right|thumb|Aron Nimzowitsch <ref>[https://en.wikipedia.org/wiki/Aron_Nimzowitsch Aron Nimzowitsch from Wikipedia]</ref> ]]
'''Nimzo''',<br/>
a chess program by primary developer [[Chrilly Donninger]], subsequently supported by members of the [[First Vienna Computer Chess Club]] (Nimzo Werkstatt) concerning [[Engine Testing|testing]], [[Knowledge|chess knowledge]], [[Opening Book|opening book]] and hardware. The program was first dubbed ''Nimzo-Guernica'' in remembrance to [https://en.wikipedia.org/wiki/Aron_Nimzowitsch Aron Nimzowitsch] and as manifest of Chrilly's [https://en.wikipedia.org/wiki/Anti-war Anti-war] engagement <ref>[https://en.wikipedia.org/wiki/Bombing_of_Guernica Bombing of Guernica from Wikiepedia]</ref>. It had its tournament debut at the [[3rd Computer Olympiad#Chess|3rd Computer Olympiad 1991]] and further played the [[DOCCC 1991]] and [[IPCCC 1991]]. At the [[WMCCC 1993]], Nimzo-Guernica aka Nimzo-2 upset [[Gideon|Mephisto Gideon]] <ref>With the help of a sign bug in [[Passed Pawn|passed pawn]] evaluation, see [[Chrilly Donninger]] ('''1999'''). ''Computer machen keine Fehler''. [[Computerschach und Spiele|CSS]] 2/99, [http://www.mustrum.de/chrilly/keine_fehler.pdf pdf] (German)</ref> and later winner [[Hiarcs]] to lead the pack after five rounds, and finished strong fourth despite 1.5 points out of the last four rounds.
=Photos & Games=
[[FILE:bronsteinchrillyjohan.gif|none|border|text-bottom|638px|link=http://www.thorstenczub.de/aegon.html]]
[[David Bronstein]] playing Nimzo by [[Chrilly Donninger]], [[Johan de Koning]] kibitzing, [[Aegon 1997]] <ref>[[David Bronstein]] vs. [[Nimzo]], Photo by [[Thorsten Czub]] from [http://www.thorstenczub.de/aegon.html Aegon 1996-97]</ref>
<pre>
[Event "AEGON 1997"]
[Site "The Hague NED"]
[Date "1997.04.17"]
[Round "02"]
[White "David Bronstein"]
[Black "NIMZO"]
[Result "0-1"]
1.e4 c5 2.Nf3 d6 3.c3 Nf6 4.Bd3 Bg4 5.h3 Bxf3 6.Qxf3 Nc6 7.O-O g6 8.Bb5 Bg7 9.e5 dxe5
10.Bxc6+ bxc6 11.Qxc6+ Nd7 12.d3 O-O 13.Nd2 Rc8 14.Qa6 Qb6 15.Qa4 Rfd8 16.Nb3 Nf6
17.Qc4 Ne8 18.Bg5 Nd6 19.Qa4 Bf6 20.Be3 Nf5 21.Qc4 Nxe3 22.fxe3 a5 23.Rad1 a4 24.Nd2
Qxb2 25.Ne4 Qe2 26.Rfe1 Qh5 27.Rd2 Bg5 28.Rf2 e6 29.Rf3 Qh6 30.Kh1 Be7 31.Ref1 Qg7
32.g4 a3 33.g5 Rd5 34.h4 Rcd8 35.Nf2 h5 36.e4 R5d7 37.Qa6 Qf8 38.Nd1 Qe8 39.Kg2 Bf8
40.R1f2 Rd6 41.Qc4 R6d7 42.Rd2 Rb7 43.Kf1 Rdb8 44.Ke2 Ra7 45.d4 Ra4 46.Qd3 cxd4
47.c4 Qc6 48.Rc2 Rbb4 49.c5 Ra5 50.Nf2 Rxc5 51.Rxc5 Rb2+ 52.Kf1 Qxc5 53.Qa6 Rxa2
54.Qa7 f6 55.gxf6 Rb2 56.Qa8 Qc1+ 57.Kg2 a2 58.Qe8 a1=Q 59.Qxg6+ Kh8 60.Qxh5+ Qh6
61.Qf7 Qd1 62.Rg3 Rxf2+ 63.Kxf2 Qhd2#
0-1
</pre>
=Nimzo-3=
Guernica and Nimzo-2 were leaf evaluators to spent 60 to 70 percent of its time in [[Evaluation|evaluation]]. The main design criterion for Nimzo-3 was combining the positional play of Nimzo-2 with the [[Tactics|tactical]] strength of a program like [[Fritz]]. Nimzo-3 therefor became a [[Chess Genius|Genius]]/Fritz like program with a complex root evaluation <ref>[[Chrilly Donninger]] ('''1996'''). ''CHE: A Graphical Language for Expressing Chess Knowledge''. [[ICGA Journal#19_4|ICCA Journal, Vol. 19, No. 4]]</ref>, called [[Oracle]] as proposed by [[Hans Berliner]] <ref>[[Hans Berliner]] ('''1987'''). ''Some Innovations Introduced by Hitech''. [[ICGA Journal#10_3|ICCA Journal, Vol. 10, No. 3]]</ref> <ref>[[Hans Berliner]] ('''1989'''). ''Some Innovations Introduced by Hitech''. [[Advances in Computer Chess 5]]</ref>, and which seems to have been first used by [[Kaare Danielsen]]. The oracle approach with very simple, mainly first-order evaluation terms at the leaves, made Nimzo-3 to spent about only 10 to 20 percent on leaf evaluation, yielding in an increased node rate of 400%.
=CHE=
The [[CHE]] and CHE++ declarative language for expressing chess knowledge using a [[GUI]] was used to incorporate [[Planning |planning]] features within the oracle used <ref>[https://www.stmintz.com/ccc/index.php?id=198528 CHE docs in English / Nimzo 3 version] by Mike S., [[CCC]], November 22, 2001</ref>.
=Commerce=
During the [[WMCCC 1996]], Nimzo was still amateur, but soon went commercial as [[MS-DOS]] program Nimzo 3.5 and the [[Windows]] program Nimzo 2000 distributed by [[Ossi Weiner|Weiner's]] [[Millennium 2000 GmbH]], later released as [[Chess Engine Communication Protocol]] compliant engine WBNimzo. Nimzo98, Nimzo99 were native [[ChessBase]] engines, followed by Nimzo 7.32 and Nimzo 8 and its derivation [[Schweinehund]] <ref>[https://www.stmintz.com/ccc/index.php?id=144598 Re: Versions of Nimzo] by Shep, [[CCC]], December 12, 2000</ref> <ref>[https://www.stmintz.com/ccc/index.php?id=265975 Re: Nimzo 4] by [[Manfred Meiler]], [[CCC]], November 19, 2002</ref>.
=Description=
given in 1999 from the [[ICGA]] tournament site <ref>[https://www.game-ai-forum.org/icga-tournaments/program.php?id=93 Nimzo's ICGA Tournaments]</ref>:
Nimzo is one of the leading professional chess programs. It combines sound positional play with extremely strong tactics. Nimzo-Paderborn is a considerable improved version of the currently commercially available programs Nimzo98, Nimzo99 and Nimzo2000.
Nimzo-Paderborn [[Learning|learns]] automatically from human grandmaster games. It is also equipped with an own Chess-Advice-Language (Che++) which allows strong human players to formulate chess-knowledge. The program can also access in its search [[Endgame Tablebases|endgame databases]]. It therefore searches regularly from the middlegame into won endgames.
<span id="Pruning"></span>
=Forward Pruning in Nimzo 2.2.1=
Following [[Pruning|forward pruning]] code appears in Nimzo's 2.2.1 search routine <ref>Nimzo: sr.c: search-tree handling (dead acor link) hosted by Roger Thormann</ref> applied at [[Frontier Nodes|frontier nodes]], notably the aggressive [[Richard Lang|Lang]] mode at pre-pre-frontier nodes or below. The source was published along with a foreword by Donninger in 2002 <ref>home.arcor.de/roger.thormann/yacdb.com/nimzo/vorwort.html Vorwort von Chrilly Donninger (German) hosted by Roger Thormann</ref> :
<pre>
if((depth <= 1) && (!extflg) && (score > beta) && (GPtr->hung.w <= KNIGHTHUNG)) {
return score;
}
if(LangModus) {
if((depth <= 3) && (!extflg) && (score > beta) && (GPtr->hung.w == 0)) {
return score;
}
}
</pre>
=See also=
* [[Brutus]]
* [[Various Classifications#ChessLegend|Chess legends]]
* [[Hydra]]
* [[Hydra 97]]
* [[WMCCC 1993#NimzoBug|Nimzo's winning white-black bug]], [[WMCCC 1993]]
* [[Schweinehund]]
=Publications=
* [[Chrilly Donninger]] ('''1992'''). ''The Relation of Mobility, Strategy and the Mean Dead Rabbit in Chess''. Heuristic Programming in Artificial Intelligence 3: the third computer olympiad (eds. [[Jaap van den Herik]] and [[Victor Allis]]), pp. 102-111. Ellis Horwood Ltd., Chichester, UK. ISBN 0-13-388265-9
* [[Chrilly Donninger]] ('''1993'''). ''Null Move and Deep Search: Selective-Search Heuristics for Obtuse Chess Programs''. [[ICGA Journal#16_3|ICCA Journal, Vol. 16, No. 3]]
* [[Thomas Mally]] ('''1993'''). ''PC Power in Braille - Nimzo Guernica: Ein PC-Schachprogramm für Blinde''. [[PC Schach]] 3/93 (German) <ref>[https://en.wikipedia.org/wiki/Braille Braille from Wikipedia]</ref>
* [[Chrilly Donninger]] ('''1996'''). ''CHE: A Graphical Language for Expressing Chess Knowledge''. [[ICGA Journal#19_4|ICCA Journal, Vol. 19, No. 4]]
=Forum Posts=
* [https://groups.google.com/d/msg/rec.games.chess.computer/fON9kA5LPYo/Jpfn6nqs3yYJ NIMZO 3 ist out now!] by [[Tom Kerrigan]], [[Computer Chess Forums|rgcc]], July 15, 1996
: [https://groups.google.com/d/msg/rec.games.chess.computer/fON9kA5LPYo/_utfvtP6RzsJ Re: NIMZO 3 ist out now!] by [[Peter Schreiner]], [[Computer Chess Forums|rgcc]], July 19, 1996
* [https://groups.google.com/d/msg/rec.games.chess.computer/lZshGHUeuxY/Kfef3R7vIkQJ Re: Nimzo3 - playing strength?] by [[Helmut Weigel]], [[Computer Chess Forums|rgcc]], August 04, 1996
* [https://groups.google.com/d/msg/rec.games.chess.computer/o57y2Ldf-ks/rlfhb1TeyYMJ NIMZO 3 !] by Komputer Korner, [[Computer Chess Forums|rgcc]], December 01, 1996
* [http://groups.google.com/group/rec.games.chess.computer/msg/f9c5ab9792a46513 Re: computer chess "oracle" ideas...] by [[Andreas Mader]], reply to [[Ronald de Man]], [[Computer Chess Forums|rgcc]], April 7, 1997
* [http://groups.google.com/group/rec.games.chess.computer/msg/2a9279e002cfec4b Re: Any word on future Nimzo plans] by [[Andreas Mader]], [[Computer Chess Forums|rgcc]], March 22, 1998
* [https://www.stmintz.com/ccc/index.php?id=148289 Nimzo 8 and piece values] by Matthew Barnett, [[CCC]], January 05, 2001
* [http://www.talkchess.com/forum/viewtopic.php?t=60404 Nimzo Engines of Millenium Chess System] by [[Norbert Raimund Leisner]], [[CCC]], June 08, 2016
=External Links=
==Chess Engine==
* [https://www.game-ai-forum.org/icga-tournaments/program.php?id=93 Nimzo's ICGA Tournaments]
==Misc==
* [https://en.wikipedia.org/wiki/Aron_Nimzowitsch Aron Nimzowitsch from Wikipedia]
* [https://en.wikipedia.org/wiki/Guernica_%28town%29 Guernica (town) from Wikipedia]
* [https://en.wikipedia.org/wiki/Bombing_of_Guernica Bombing of Guernica from Wikiepedia]
* [https://en.wikipedia.org/wiki/Guernica_%28painting%29 Guernica (painting) from Wikipedia]
=References=
<references />
'''[[Engines|Up one Level]]'''
