ChessV (short for Chess Variants) is a

free Free may refer to: Concept * Freedom, the ability to act or change without constraint or restriction * Emancipate, attaining civil and political rights or equality * Free (''gratis''), free of charge * Gratis versus libre, the difference betw ...

computer program A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. It is one component of software, which also includes software documentation, documentation and other intangibl ...

designed to play many

chess variant A chess variant is a game related to, derived from, or inspired by chess. Such variants can differ from chess in many different ways. "International" or "Western" chess itself is one of a family of games which have related origins and could be co ...

s. ''ChessV'' is an open-source, universal chess variant program with a graphical user-interface, sophisticated AI, support for opening books and other features of traditional chess programs. The developer of this program, Gregory Strong, has been adding more variants with each release of ''ChessV''. Over 100 chess variants are supported, including the developer's few own variants and other exotic variants, and can be programmed to play additional variants. ''ChessV'' is designed to be able to play any game that is reasonably similar to

chess Chess is a board game for two players. It is an abstract strategy game that involves Perfect information, no hidden information and no elements of game of chance, chance. It is played on a square chessboard, board consisting of 64 squares arran ...

. ''ChessV'' is one of only a few such programs that exist. The source code of this program is freely available for download as well as the executable program. As of ChessV 0.93, it is possible to customize the variants it supports. Of all chess variants supported, two of the most-played variants are probably

Fischer Random Chess Chess960, also known as Fischer Random Chess, is a chess variant that randomizes the starting position of the pieces on the back rank. It was introduced by former world chess champion Bobby Fischer in 1996 to reduce the emphasis on opening prep ...

and

Grand Chess Grand Chess is a large-board chess variant invented by Dutch games designer Christian Freeling in 1984. It is played on a 10×10 board, with each side having two additional pawns and two new pieces: the ''marshal'' and the ''cardinal''. * Th ...

. ''ChessV'' is capable of playing: * 2 variants on 6×6 squares * 17 variants on 8×8 squares * 15 variants on 10×8 squares (including 10 Capablanca Chess variants) * 15 variants on 10×10 squares * 3 variants on 12×8 squares Some of the provided variants can be customized in their details. While users can create custom variants with ChessV 0.93, it needs to be recompiled, which is tedious when programming. ChessV 2.0+ fixes this, using a scripting language. While the pieces in a custom variant have to be chosen from a limited list, this allows ChessV to play hundreds or thousands of variants of each game it directly supports.

Engine features

Searching Searching may refer to: Music * " Searchin", a 1957 song originally performed by The Coasters * "Searching" (China Black song), a 1991 song by China Black * "Searchin" (CeCe Peniston song), a 1993 song by CeCe Peniston * " Searchin' (I Gott ...

: Alpha-Beta Nega-Max Principal variation search,

Iterative deepening In computer science, iterative deepening search or more specifically iterative deepening depth-first search (IDS or IDDFS) is a state space/graph search strategy in which a depth-limited version of depth-first search is run repeatedly with incre ...

, Null-move Forward

Pruning Pruning is the selective removal of certain parts of a plant, such as branches, buds, or roots. It is practiced in horticulture (especially fruit tree pruning), arboriculture, and silviculture. The practice entails the targeted removal of di ...

, Static Exchange Evaluation (SEE). :: ''Search Extensions'':

check Check or cheque, may refer to: Places * Check, Virginia Arts, entertainment, and media * ''Check'' (film), a 2021 Indian Telugu-language film * "The Check" (''The Amazing World of Gumball''), a 2015 episode of ''The Amazing World of Gumball'' ...

extension, recapture extension, null-move threat extension, PV extension, Futility Pruning and Razoring, History

Heuristic A heuristic or heuristic technique (''problem solving'', '' mental shortcut'', ''rule of thumb'') is any approach to problem solving that employs a pragmatic method that is not fully optimized, perfected, or rationalized, but is nevertheless ...

, Killer-move heuristic. * Evaluation: Piece-square tables,

Pawn Pawn most often refers to: * Pawn (chess), the weakest and most numerous chess piece in the game * Pawnbroker or pawnshop, a business that provides loans by taking personal property as collateral Pawn or The Pawn may also refer to: Places * Pa ...

structure evaluation, Mobility evaluation,

King King is a royal title given to a male monarch. A king is an Absolute monarchy, absolute monarch if he holds unrestricted Government, governmental power or exercises full sovereignty over a nation. Conversely, he is a Constitutional monarchy, ...

safety, King tropism,

Lazy evaluation In programming language theory, lazy evaluation, or call-by-need, is an evaluation strategy which delays the evaluation of an Expression (computer science), expression until its value is needed (non-strict evaluation) and which avoids repeated eva ...

. *

Hash Tables In computer science, a hash table is a data structure that implements an associative array, also called a dictionary or simply map; an associative array is an abstract data type that maps Unique key, keys to Value (computer science), values. ...

Transposition table {{no footnotes, date=November 2017 A transposition table is a cache of previously seen positions, and associated evaluations, in a game tree generated by a computer game playing program. If a position recurs via a different sequence of moves, the ...

, Pawn structure table, Evaluation

cache Cache, caching, or caché may refer to: Science and technology * Cache (computing), a technique used in computer storage for easier data access * Cache (biology) or hoarding, a food storing behavior of animals * Cache (archaeology), artifacts p ...

, Repetition detection. Since ChessV 2.2, the engine can be set to adjust to their player's needs: * Transposition Table Size can be adjusted. * The engine can be allowed for variance of play. * Weaken the chess engine to be human-beatable even for beginners.

Current limitations

* No games with more than two players are supported. * No games with randomness or hidden information are supported. * No ability to edit the board mid-game is provided.

Supported games

ChessV supports many variants. Other than chess, it supports: * Alice Chess, Almost Chess, Archchess,

Berolina Chess The Berolina pawn (also known as Berlin pawn, anti-pawn, or simply Berolina) is a popularPritchard (2007), p. 59: "Tournaments have been held, combination games have been tried, and 'Berolina pawns' have long been popular with problemists. (''Funk ...

, Bird's Chess, Capablanca Chess and its variants, Carrera's Chess, Chess480, Chess and a Half,https://www.chessvariants.com/rules/chess-and-a-half Chess and a Half,

Chess with Different Armies Chess with different armies (or Betza's Chess or Equal Armies) is a chess variant invented by Ralph Betza in 1979. Two sides use different sets of fairy pieces. There are several armies of equal strength to choose from, including the standard FI ...

, Courier Chess, Cylindrical Chess, Diagonal Chess, Diamond Chess, Doublemove chess, Embassy Chess, Eurasian Chess, Extinction Chess, Fischer Random Chess (Chess960), Great Chess, Great Shatranj,

, Grotesque Chess, Janus Chess,

Kinglet A kinglet is a small bird in the family Regulidae. Species in this family were formerly classified with the Old World warblers. "Regulidae" is derived from the Latin word ''regulus'' for "petty king" or prince, and refers to the coloured crowns ...

, Ladorean Chess, Legan's Game,

Los Alamos Chess Los Alamos chess (or anti-clerical chess) is a chess variant played on a 6×6 board without bishops. This was the first chess-like game played by a computer program. This program was written at Los Alamos Scientific Laboratory by Paul Stein and ...

Makruk Makruk (; ; ), or Thai chess (; ; ), is a Strategy game, strategy board game that is descended from the 6th-century Indian game of chaturanga or a close relative thereof, and is therefore related to chess. It is part of the family of chess varian ...

Omega Chess Omega Chess is a commercial chess variant designed and released in 1992 by Daniel MacDonald. The game is played on a 10×10 board with four extra squares, each added diagonally adjacent to the corner squares. The game is laid out like standard che ...

, Opulent Chess, Roman Chess, Royal Court,

Shatranj Shatranj (, ; from Middle Persian ) is an old form of chess, as played in the Sasanian Empire. Its origins lie in the South Asian game of chaturanga. Modern chess gradually developed from this game, as it was introduced to Europe by contacts in ...

, Shatranj Kamil, Sosarian Chess, Switching Chess, TenCubed Chess, Three Checks Chess, and more infamous variants. Since ChessV can be programmed to play additional variants, here are a few examples: * Almost Chess, Enep, Butterfly Chess,

Nightrider Night Rider, Nightrider, or variants thereof may refer to: Literature * ''Night Rider'' (novel), a 1939 novel by Robert Penn Warren * ''Night Rider'', a 2001 novel by W. A. Harbinson written under the Shaun Clarke pseudonym * Nightrider (DC C ...

chess and Janus Kamil.

Syntax

ChessV code is saved as the extension ".cvc" (ChessV Code). Its syntax is reasonably similar to C#. The scripting language is mostly stable, but creating new rules for new pieces is not supported yet. Here is an example of "Almost Chess" in .cvc code: Game 'Almost Chess' : Chess

Competitions

ChessV software won third place in a 2004 Gothic Chess Computer World Championship.

References

External links

ChessV download page

site about Chess Variants, mentions ChessV in several articles
{{Chess variants Chess software Chess variants Free chess software Windows games Windows-only free software