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Paradise, (Pattern recognition applied to directing search)
a knowledge based chess program written at Stanford University in the late 70s by David Wilkins. Paradise was written in MacLisp, a dialect of the Lisp programming language developed at MIT within Project MAC. Paradise' goal was to find the best move in tactically sharp middlegame positions from the game of chess masters.

Pattern and Plans

Like human players, the program had a large number of stored "patterns", and analyzing a position involved matching these patterns to suggest plans for attack or defense. By communicating plans down the tree, the analysis was verified and possibly corrected by a small search of the game tree (tens of positions) inluding specialized causality facility and quiescence search [2]. There were production rules to produce plans, implementing such concepts as checkmate, fork, skewer, and trapping the piece, etc..

A plan generator produced tactical plans in a Plan Language. The program is capable of finding very deep combinations because no limit is placed on its search depth. It searches for moves as long as a plan is continuing to work [3].

Win at Chess

While Paradise was able to solve most of 92 positions picked from the first 100 from Win at Chess, with averaged three minutes thirty-three seconds for each solved position on a PDP-10 [4], it was not able to play a complete reasonable game of chess due not further implemented knowledge employable in strategic, none-tactical positions, especially during the endgame. Controlling the search by recognizers, i.e. the amount to extend or to reduce if a move is accordant to a plan or not is still hot topic.

See also



Forum Posts

External Links

Frank Zappa, Jean-Luc Ponty, George Duke, Tom Fowler, Bruce Fowler, Ruth Underwood, Ian Underwood, Ralph Humphrey


  1. Paradise by Jan Brueghel the Younger (c. 1620). Oil on oak. Gemäldegalerie, Berlin, Paradise from Wikipedia
  2. Comparison: Paradise and Symbolic by Steven Edwards, CCC, February 13, 2004
  3. Tristan Caulfield (2004). Acquiring and Using Knowledge in Computer Chess. B.Sc. Computer Science, University of Bath, pdf, 4.2.2 PARADISE, pp. 12
  4. Re: Paradise performance by Steven Edwards, CCC, August 22, 2003
  5. Papers on Chess by David E. Wilkins

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