AI_Chess - peregrineshahin/ChessProgrammingWiki GitHub Wiki
title: AI Chess
AI Chess, (A.I. Chess)
a chess program by Marty Hirsch and predecessor of MChess. AI Chess was written in 8086 assembly language to ran on an IBM PC under DOS [1]. It played the ACM 1988 in Orlando, the WCCC 1989 in Edmonton and the WMCCC 1989 in Portorož [2].
Description
given in the WCCC 1989 booklet [3] :
A.I. Chess uses a fairly complicated algorithm combining full-width search, [selective search](Selectivity "Selectivity"), and a "layered" [quiescence search](Quiescence_Search "Quiescence Search") which behaves differently at different levels in the search tree. The program performs an [iterative](Iterative_Deepening "Iterative Deepening") full-width search using a modified form of the [Principal-Variation-Search](Principal_Variation_Search "Principal Variation Search") (PVS) algorithm. On top of this, it does a combined selective/quiscence analysis. A.I. Chess has the unusual feature of sometimes re-searching a "[quiscence node](Quiescent_Node "Quiescent Node")" with a full-width investigation.
The quiescence search incorporates a detailed "threat analysis" and therefore, the program spots may combinations long before a contrasting "[brute force](Brute-Force "Brute-Force")" approach would find them. The gain (from needing less full-width plies) seems to exceed the loss in speed by a significant amount.
[Position evaluation](Evaluation "Evaluation") starts by considering if the side to move is threatened with [pawn promotion](Promotions "Promotions"), [check](Check "Check"), or [double attack](Double_Attack "Double Attack"), or has [trapped](Trapped_Pieces "Trapped Pieces"), [pinned](Pin "Pin"), or [skewered](Skewer "Skewer") pieces. Penalties similar to swap-off scores are imposed if the position is too deep to merit a re-search. [Scores](Score "Score") are then added for other [tactical patterns](Tactics "Tactics"), pressure on pieces and pawns, development, [King safety](King_Safety "King Safety"), [passed pawns](Passed_Pawn "Passed Pawn"), [pawn structure](Pawn_Structure "Pawn Structure"), [outposts](Outposts "Outposts"), and [mobility](Mobility "Mobility").
Some types of [endgame positions](Endgame "Endgame") are scored differently, by [pattern recognition](Pattern_Recognition "Pattern Recognition") processing. The program is alert to simplifications, and to tactics involving passed pawns.
See also
External Links
References
- ↑ Monty Newborn, Danny Kopec (1989). Results of The Nineteenth ACM North American Computer Chess Championship. Communications of the ACM, Vol. 32, No. 10, pdf
- ↑ AI Chess' ICGA Tournaments
- ↑ Kings Move - Welcome to the 1989 AGT World Computer Chess Championship. Edmonton, Alberta, Canada, Courtesy of Peter Jennings, from The Computer History Museum, pdf