Y!

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**Y!** (Why Not), 
a chess program written by primary author [[Ulf Rathsman]], supported by [[Lars Hjörth]] and [[Opening Book Authors|book author]] [[Sandro Necchi]]. It was written in [[6502]] [[Assembly|assembly]] and played tournaments on the [[6502#TK20|TurboKit TK20]] by //Schaetzle+Bsteh// <ref>[[http://www.schach-computer.info/wiki/index.php/TurboKit|TurboKit – Schachcomputer.info Wiki]]</ref>. Y! competed the [[WMCCC 1988]] as Y!88 and the [[WMCCC 1989]] and [[WCCC 1989]] as Y!89 (Why Not 89).

=Photos=
|| [[image:WMCCC88YNot.jpg width="640"]] ||
|| [[Ulf Rathsman]] and [[Sandro Necchi]] of [[Y!|Y!88]] at the [[WMCCC 1988]] in [[http://en.wikipedia.org/wiki/Almer%C3%ADa|Almería]] <ref>Image by [[László Lindner]] from [[László Lindner]] (**1989**).//Die wiederauferstandene Mikro-Weltmeisterschaft - 8.Mikroschachcomputer - WM 1988 in Almeria//. [[https://de.wikipedia.org/wiki/Rochade_Europa|Europa-Rochade]], 01/02-1989, [[http://schaakcomputers.nl/hein_veldhuis/database/files/11-1988,%20Europa-Rochade,%20Die%208.%20Mikroschachcomputer-WM%201988%20in%20Almeria.pdf|pdf]] hosted by [[Hein Veldhuis]] (German)</ref> ||

=Description=
based on the [[WCCC 1989]] booklet <ref>[[http://www.computerhistory.org/chess/full_record.php?iid=doc-434fea055cbb3|Kings Move - Welcome to the 1989 AGT World Computer Chess Championship.]] Edmonton, Alberta, Canada, Courtesy of [[Peter Jennings]], from [[The Computer History Museum]], [[http://archive.computerhistory.org/projects/chess/related_materials/text/3-1%20and%203-2%20and%203-3%20and%204-3.1989_WCCC/1989%20WCCC.062302028.sm.pdf|pdf]]</ref>:
|| {{Y!89 uses a full, partly extended, width iterative [[Principal Variation Search|principal variation search]] with [[Captures|capture]] and [[Promotions|promotion]] [[Quiescence Search|searches]] in [[Quiescent Node|terminal nodes]]. The program is designed to be used in a cheap commercial environment, thus the work [[Memory|memory]] is still just 4 kbytes of [[Memory#RAM|RAM]], and the good old [[6502]] eight bit processor is used in tournaments emulated by the also commercially available //Turbo kit//. The [[Search|search]] is fast for a micro, and includes detection of [[Repetitions|repeated positions]] (actual as well as potential), and performs [[Extensions|extensions]] for [[Check Extensions|check evasions]], [[Passed Pawn Extensions|passed pawn moves]] and some king moves in [[Pawn Endgame|pawn endgames]].}}

{{Most of the [[Material|material]] and [[Evaluation of Pieces|positional evaluation]] is made [[Incremental Updates|incrementally]] by the means of material value tables and [[Piece-Square Tables|positional score boards]] for each piece type, created once for each position of the game with the computer to move. Some "absolute" evaluation is also done, e.g. for static evaluation of [[Unstoppable Passer|unstoppable passed pawns]] and [[Pawn Structure|pawn structure]].}} ||

=External Links=
* [[http://www.game-ai-forum.org/icga-tournaments/program.php?id=356|Y!'s ICGA Tournaments]]
* [[http://www.game-ai-forum.org/icga-tournaments/program.php?id=455|Why Not 89's ICGA Tournaments]]
* [[http://www.schach-computer.info/wiki/index.php/Conchess|Conchess]] – [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info Wiki]] (German) <ref>[[Karsten Bauermeister]] (**1998**). //Die Geschichte der Conchess-Schachcomputer//. [[Computerschach und Spiele]], Heft 4, August-September 1998</ref>

=References= 
<references />
=What links here?= 
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