Mini Chess

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|| [[image:Acetronic.jpg link="http://www.flickr.com/photos/10261668@N05/859036624/in/set-72157600922172552/"]] ||~ || **Mini Chess**, (SciSys Mini Chess)
along with [[Mini Chess#Junior|Junior Chess]] and [[Mini Chess#Graduate|Graduate Chess]], a series of portable [[Dedicated Chess Computers|dedicated chess computers]] manufactured and sold by [[Saitek|SciSys]], first released in early 1981. The computers had a [[http://en.wikipedia.org/wiki/Hitachi_Ltd.|Hitachi]] **HD44801** 4-bit [[http://en.wikipedia.org/wiki/CMOS|CMOS]] [[http://en.wikipedia.org/wiki/Microcontroller|microcontroller]] with 2 kibi of 10-bit word [[Memory#ROM|ROM]], 128 10-bit words of pattern ROM supported by pattern generation instructions with table lookup capability, and **160** [[Nibble|nibbles]] or digits (80 [[Byte|bytes]]) of [[Memory#RAM|RAM]] <ref>[[http://www.ic-on-line.cn/view_download.php?id=1100207&file=0052%5Chd44801_398306.pdf|HD44801_398306.PDF Datasheet Download --- IC-ON-LINE]]</ref>, running at 400 KHz. 

The programs were delivered by [[Philidor Software]], developed by [[Mark Taylor]] under guidance of [[David Levy]], who contributed the basic chess algorithm <ref>[[http://www.schach-computer.info/wiki/index.php/Levy,_David|David Levy interview]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]]</ref> including [[Promotions|promotions]], [[En passant|en passant]], and [[Castling|castling]], and even managed [[Checkmate|mate]] with KR v K in some versions all in astonishing 160 nibbles of RAM. A piece of work that Mark Taylor is still rightly proud of today <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>.  ||
|| Acetronic aka Mini Chess <ref>[[http://www.flickr.com/photos/10261668@N05/859036624/in/set-72157600922172552/|Acetronic]] from [[http://www.flickr.com/photos/10261668@N05/sets/72157600922172552/|Scisys/Saitek | Photo collection]] by [[Steve Blincoe|Chewbanta]]</ref> ||~ ||^  ||
[[toc]]
=160 Nibble Challenge=
160 nibbles of RAM is a challenge. The HD44801 has an internal 4 word return [[Stack|stack]], so one may assume a maximum [[Depth|search depth]] of 4, but one has to be careful with external [[http://en.wikipedia.org/wiki/Interrupt|interrupts]], i. e. from keyboard or timer, since they cause an implicit call to an [[http://en.wikipedia.org/wiki/Interrupt_handler|interrupt handler]], pushing the instruction pointer on the internal stack as well, with the possibility to cause an [[http://en.wikipedia.org/wiki/Stack_overflow|stack overflow]]. One may better implement a simple [[Iterative Search|iterative search]], called after [[Make Move|making a move]] at the [[Root|root]] within its [[Iterative Deepening|iterative deepening]] framework. 

The board is apparently represented by an [[Incremental Updates|incremental updated]] [[8x8 Board|8x8]] [[Array|array]] of nibbles. The ply stack entry consists of [[En passant|en passant]]- and [[Castling Rights|castling rights]], the [[Moves|move]] to [[Unmake Move|unmake]], likely 3 nibbles [[Encoding Moves|12-bit from-to encoding]] also interpreted as state of a deterministic [[Move Generation|move generator]], and [[Alpha|alpha]], while [[Beta|beta]] might be restored from alpha of the previous ply in [[Negamax|negamax]] manner. Of course, with such a minimalistic design, [[Move Ordering|move ordering]] is a big issue, and how to utilize the remaining nibbles in a most efficient manner, considering [[MVV-LVA]] and possibly maintaining a small [[Triangular PV-Table|triangular PV-table]] say for four plies.

=Derivatives=
**Mini Chess** was the basic model with [[http://en.wikipedia.org/wiki/Keypad|keypad]] and [[http://en.wikipedia.org/wiki/Seven-segment_display|seven-segment]] [[http://en.wikipedia.org/wiki/Liquid_crystal_display|LCD]] to display move coordinates and small status messages, also sold in the UK under the marketing company name //Acetronic//. 
[[#Junior]]
==Junior Chess==
|| [[image:juniorChess.jpg link="http://www.flickr.com/photos/10261668@N05/858189105/in/set-72157600922172552"]] ||~ || **Junior Chess** had almost the same hardware and program than Mini Chess, but an integrated travel pegboard. ||
|| Junior Chess <ref>[[http://www.flickr.com/photos/10261668@N05/858189105/in/set-72157600922172552|Junior Chess]] with [[FIDE]] recommendation for novice and junior chess players, [[http://www.flickr.com/photos/10261668@N05/sets/72157600922172552/|Scisys/Saitek | Photo collection]] by [[Steve Blincoe|Chewbanta]]</ref> ||~ ||^ ||
[[#Graduate]]
==Graduate Chess==
|| [[image:graduateChess.jpg link="http://www.flickr.com/photos/10261668@N05/858180171/in/set-72157600922172552"]] ||~ || Like [[Mini Chess#Junior|Junior Chess]], **Graduate Chess** was almost identical to Mini Chess, also with an integrated travel pegboard. ||
|| Graduate Chess  <ref>[[http://www.flickr.com/photos/10261668@N05/858180171/in/set-72157600922172552|Graduate Chess]] from [[http://www.flickr.com/photos/10261668@N05/sets/72157600922172552/|Scisys/Saitek | Photo collection]] by [[Steve Blincoe|Chewbanta]]</ref>||~ ||^ ||

==CXG==
The 4-bit program initiated [[Eric White|Eric White's]] involvement in computer chess business and long time collaboration with Levy, when [[http://en.wikipedia.org/wiki/Hong_Kong|Hong Kong]] based manufacturer //White and Allcock//, forerunner of [[Newcrest Technology]] introduced the [[Newcrest Technology#CXG|CXG]] brand in 1981 with [[CXG Sensor Computachess]] <ref>[[http://www.schach-computer.info/wiki/index.php/CXG_Sensor_Computachess|CXG Sensor Computachess]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info Wiki]]</ref> <ref>[[http://www.schach-computer.info/wiki/index.php/CXG_Pocket_Chess|CXG Pocket Chess]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info Wiki]]</ref>. It was further adapted for the more advanced **HMCS40** 4-bit singlechip processor <ref>[[http://www.ic-on-line.cn/view_download.php?id=1124980&file=0065%5Chd614048_511862.pdf|HD614048_511862.PDF Datasheet Download --- IC-ON-LINE]]</ref>.

==Chess Cards==
|| [[image:FidelityChessCard.JPG width="320" link="http://www.flickr.com/photos/10261668@N05/2071464244/in/set-72157600922174174"]] ||~ || In the late 80 and early 90, the 4-Bit program appeared in low cost chess card computers by [[Newcrest Technology#CXG|CXG]] <ref>[[http://www.schach-computer.info/wiki/index.php/CXG_Sphinx_Chess_Card|CXG Sphinx Chess Card]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]]</ref> and [[Fidelity Electronics]] <ref>[[http://www.schach-computer.info/wiki/index.php/Fidelity_Chess_Card|Fidelity Chess Card]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]] (German)</ref>, at that time already acquired by [[Hegener & Glaser]]. ||
|| Fidelity Chess Card <ref>[[http://www.flickr.com/photos/10261668@N05/2071464244/in/set-72157600922174174|Fidelity Chess Card]] from [[http://www.flickr.com/photos/10261668@N05/sets/72157600922174174/with/2071464268/|Exotic: Photo collection]] by [[Steve Blincoe|Chewbanta]]</ref> ||~ ||^ ||

=See also=
* [[Junior]]
* [[Mini]]
* [[Sensor Chess#MoveGeneration|Move Generation with 256 bytes RAM or less?]]
* [[Novag Micro Chess]]
* [[Philidor Software]]

=External Links=
* [[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]]
* [[http://www.chesscomputeruk.com/html/scisys_and_novag___the_early_y.html|Scisys and Novag : The Early Years]] from [[http://www.chesscomputeruk.com/index.html|Chess Computer UK]] by [[Mike Watters]]
* [[http://www.flickr.com/photos/10261668@N05/sets/72157600922172552/|Scisys/Saitek | Photo collection]] by [[Steve Blincoe|Chewbanta]]

==Mini Chess==
* [[http://www.chesscomputeruk.com/html/mini_chess.html|Mini Chess]] from [[http://www.chesscomputeruk.com/index.html|Chess Computer UK]] by [[Mike Watters]]
* [[http://electronicchess.free.fr/prehistory.html#minichess|Mini Chess | My Chess Computers]]
* [[http://www.schach-computer.info/wiki/index.php/SciSys_Mini_Chess|SciSys Mini Chess]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]] (German)

==Junior Chess==
* [[http://www.chesscomputeruk.com/html/junior_chess.html|Junior Chess]] from [[http://www.chesscomputeruk.com/index.html|Chess Computer UK]] by [[Mike Watters]]
* [[http://electronicchess.free.fr/prehistory.html#juniorchess2|Scisys Junior Chess | My Chess Computers]]
* [[http://www.schach-computer.info/wiki/index.php/SciSys_Junior_Chess|SciSys Junior Chess]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]] (German)

==Graduate Chess==
* [[http://www.chesscomputeruk.com/html/graduate_chess.html|Graduate Chess]] from [[http://www.chesscomputeruk.com/index.html|Chess Computer UK]] by [[Mike Watters]]
* [[http://electronicchess.free.fr/prehistory.html#acetronic|Acetronic Graduate Chess | My Chess Computers]]

==Chess Cards==
* [[http://www.spacious-mind.com/html/chess_card.html|Fidelity Chess Card Electronic Chess Computer]] from [[The Spacious Mind]]
* [[http://www.ismenio.com/chess_fidelity_chess_card.html|Ismenio's chess computer collection | Fidelity Chess Card 6115]]
* [[http://www.schach-computer.info/wiki/index.php/CXG_Pocket_Chess|CXG Pocket Chess]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]] (German)
* [[http://www.schach-computer.info/wiki/index.php/CXG_Sphinx_Chess_Card|CXG Sphinx Chess Card]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]] (German)
* [[http://www.schach-computer.info/wiki/index.php/Fidelity_Chess_Card|Fidelity Chess Card]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]] (German)
* [[http://www.schach-computer.info/wiki/index.php/Fidelity_Chess_Pal|Fidelity Chess Pal]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]] (German)
* [[http://www.schach-computer.info/wiki/index.php/Fidelity_Micro_Chess_Challenger|Fidelity Micro Chess Challenger]] from [[http://www.schach-computer.info/wiki/index.php/Hauptseite_En|Schachcomputer.info - Wiki]] (German)

=References= 
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=What links here?= 
[[include page="Mini Chess" component="backlinks" limit="40" ]]
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