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Engines * Coko
Coko , (COKO III)
a chess program by
Dennis Cooper and
Ed Kozdrowicki which competed the first four
ACM North American Computer Chess Championships ,
ACM 1970 ,
ACM 1971 ,
ACM 1972 (Coko III ) and
ACM 1972 (Coko IV ). Coko, the Cooper-Kozdrowicki chess program was written in
Fortran as a highly selective tree searcher in the spirit of a
Shannon Type B program using a tree pruning system (TPS) consists of a set of commands designed for programming heuristic tree searches [1] .
Descriptions# Abstract# COKO III: The Cooper-Koz Chess Program,
Communications of the ACM , Vol. 16, 7 [2]
COKO III is a chess player written entirely in Fortran . On the [ IBM 360 - 65 ]( IBM_360 "IBM 360" ), COKO III plays a minimal chess game at the rate of .2 sec cpu time per move , with a level close to lower chess club play . A selective tree searching procedure controlled by tactical chess logistics allows a deployment of multiple minimal game calculations to achieve some optimal move selection . The tree searching algorithms are the heart of COKO ' s effectiveness , yet they are conceptually simple . In addition , an interesting phenomenon called a tree searching catastrophe has plagued COKO ' s entire development just as it troubles a human player . Standard exponential growth is curbed to a large extent by the definition and trimming of the Fisher set . A clear distinction between tree pruning and selective tree searching is also made . Representation of the chess environment is described along with a strategical preanalysis procedure that maps the Lasker regions . Specific chess algorithms are described which could be used as a command structure by anyone desiring to do some chess program experimentation . A comparison is made of some mysterious actions of human players and COKO III .
Board Representation# Figure 2 from COKO III: The Cooper-Koz Chess Program explains COKO’s
10x12 Board Chess environment [3] :
Chess environment representation : minimal game board. (a) The chessboard represented by a
linear array .
(b) Representation of
pieces , empty
squares and border squares. (c) Move
directions for
King and
Queen .
(d) The
Knight dictates that two rows of border squares surround the
8 X 8 game board .
Columns 10 and 1 are considered adjacent.
Search# As described by Cooper in the 1971 Panel [4] , Coko III does not use
Alpha-Beta :
Although the alpha - beta procedure is a great time saving method , it is unclear at this stage of program development what the full significance of applying such a method to a tactical - strategical game tree would be . Coko III does save the chess tree with periodic pruning to allow for the addition of more branches .
Man-Machine Studies# International Journal of Man-Machine Studies [5]
The performance capabilities of the best computer chess programs are compared with their human counterparts with emphasis being placed on machine behavior limits . A grandmaster usually spends a lifetime collecting knowledge or information about the game . Some of this knowledge is given to COKO in the form of a 12 000 - line FORTRAN program . Using this knowledge COKO plays very poorly but at the super rate of approximately one move / see . The use of a brute - force selective tree - searching procedure yields an order of magnitude improvement in performance at the standard rate of 3 min / move . Perhaps three orders of magnitude additional improvement is needed to defeat the world champion , a gap which must be bridged , if ever , by programming more chess knowledge into the machine . This paper discusses the “ tree - searching catastrophe ” as a natural phenomenon that plagues selective tree searching for both man and machine . In addition so - called “ interminimal - game communication ” is considered as a natural , powerful procedure frequently used by humans to guide their selective search and as a point of emphasis for future development . It is concluded that COKO ' s development is just beginning , with no immediate barriers to progress , and no lack of ideas for improvement . At present COKO combines brilliant solutions to individual board position puzzles with unimaginable blunders .
Mate in one?# During the
ACM 1971 , Coko III offered a pawn versus
Genie which, if accepted, would permit a mating sequence 17 plies deep. The pawn was taken, mate was announced, and the predicted line was followed, until … [6]
8/pp6/2p2p2/6p1/1P6/2Q1P3/k1K2PPP/5B1R w - - 0 38
Apparently due to a
bug , Coko III found other moves better than mate in one and threw the win …
[Event "ACM 1971"]
[Site "Chicago"]
[Date "1972.08.03"]
[Round "2"]
[White "Coko III"]
[Black "Genie"]
[Result "0-1"]
1.d4 d5 2.Nf3 Nf6 3.Bg5 Bg4 4.Nc3 Ne4 5.Ne5 Be6 6.Nxe4 dxe4 7.c4 Nd7 8.Nxd7 Bxd7 9.e3 f6
10.Bf4 Be6 11.Qh5+ Kd7 12.d5 Bg8 13.Qf5+ e6 14.dxe6+ Bxe6 15.Qxe4 c6 16.Rd1+ Ke8 17.Rxd8+
Kxd8 18.Qxe6 Bb4+ 19.Ke2 Re8 20.Qg4 g6 21.Qh4 g5 22.Qxh7 Be7 23.Qd3+ Kc8 24.Bd6 Kd7 25.Bxe7+
Kxe7 26.Qh7+ Ke6 27.Qe4+ Kd6 28.c5+ Kxc5 29.Qd4+ Kb5 30.Kd1+ Ka5 31.b4+ Ka4 32.Qc3 Rad8+
33.Kc2 Rd2+ 34.Kxd2 Rd8+ 35.Kc2 Rd2+ 36.Qxd2 Ka3 37.Qc3+ Kxa2 38.Kc1 f5 39.Kc2 f4 40.Kc1 g4
41.Kc2 f3 42.Kc1 fxg2 43.Kc2 gxh1=Q 44.Kc1 Qxf1+ 45.Kd2 Qxf2+ 46.Kc1 Qg1+ 47.Kc2 Qxh2+ 48.Kc1
Qh1+ 49.Kc2 Qb1+ 50.Kd2 g3 51.Qc4+ Qb3 52.Qxb3+ Kxb3 53.e4 Kxb4 54.e5 g2 0-1
Mater# According to
Monroe Newborn in 1975, the chess
mating
combinations program
Mater by
George Baylor and
Herbert Simon , initially written in
IPL V , was ported to
Fortran and incorporated into Coko [7] :
MATER is written by George Baylor and Simon in FORTRAN . It is able to search to great depths for checkmates . MATER is presently part of the Cooper - Kozdrowicki program . While MATER is an interesting program in its own right , the opportunity to checkmate one ' s opponent plays a relatively small computational part of the game of chess , and its inclusion in the Cooper - Kozdrowicki program does not seem to add measurably to the program ' s strength .
Publications# Edward W. Kozdrowicki ,
John S. Licwinko ,
Dennis W. Cooper (1971 ). Algorithms for a minimal chess player: A blitz player .
International Journal of Man-Machine Studies, Vol 3, 2 Edward W. Kozdrowicki ,
Dennis W. Cooper (1973 ). COKO III: The Cooper-Koz Chess Program .
Communications of the ACM , Vol. 16, 7Edward W. Kozdrowicki ,
Dennis W. Cooper (1973 ). COKO III and the future of inter-snap judgment communication . Proceedings of the ACM annual conferencePaul Rushton ,
Tony Marsland (1973 ). Current Chess Programs: A Summary of their Potential and Limitations . INFOR Journal of the Canadian Information Processing Society Vol. 11, No. 1,
pdf Edward W. Kozdrowicki ,
Dennis W. Cooper (1974 ). COKO III: The Cooper-Kozdrowicki chess program .
International Journal of Man-Machine Studies Vol. 6, 6 External Links# References# ↑
Edward W. Kozdrowicki (1968 ). An adaptive tree pruning system: A language for programming heuristic tree searches . Proceedings of the 1968 23rd ACM national conference↑
Edward W. Kozdrowicki ,
Dennis W. Cooper (1973 ). COKO III: The Cooper-Koz Chess Program .
Communications of the ACM , Vol. 16, 7↑
Edward W. Kozdrowicki ,
Dennis W. Cooper (1973 ). COKO III: The Cooper-Koz Chess Program .
Communications of the ACM , Vol. 16, 7, Fig. 2↑
Ben Mittman (1971 ). Computer Chess Programs (Panel) .
pdf from
The Computer History Museum ↑
Edward W. Kozdrowicki ,
Dennis W. Cooper (1974 ). COKO III: The Cooper-Kozdrowicki chess program .
International Journal of Man-Machine Studies Vol. 6, 6 ↑
George Atkinson (1998 ). Chess and Machine Intuition . (Intellect Ltd.) pp 63↑
Monroe Newborn (1975 ). Computer Chess . Academic Press, New York, N.Y. p. 26↑
Re: Old programs CHAOS and USC by
Dann Corbit ,
CCC , July 11, 2015Up one level