COKO III: The Cooper-Koz Chess Program

COKO III is a chess player written entirely
in Fortran.  On the IBM 360-65, 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 Fischer 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.

CACM July, 1973

Kozdrowicki, E. W.
Cooper, D. W.

artificial intelligence, selective searching, tree
searching, tree searching catastrophe, heuristic 
programming,chess algorithms, Lasker regions, Fischer
set, minimal chess game, strategical, tactical, 
tactical control mode, game playing, alpha beta, machine
learning, concept formation, command structure, 
minimax, computer chess tournament, auxiliary minimal game

3.60 3.66 3.74 4.22

CA730703 JB January 23, 1978  1:07 PM

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