ChessV (short for Chess Variants) is a

free Free may refer to: Concept * Freedom, having the ability to do something, without having to obey anyone/anything * Freethought, a position that beliefs should be formed only on the basis of logic, reason, and empiricism * Emancipate, to procur ...

computer program A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer program ...

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, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to disti ...

. ''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 Fischer random chess, also known as Chess960 (often read in this context as 'chess nine-sixty' instead of 'chess nine hundred sixty'), is a variation of the game of chess invented by the former world chess champion Bobby Fischer. Fischer announ ...

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''. * The ...

. ''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 Capablanca chess (or Capablanca's chess) is a chess variant invented in the 1920s by World Chess Champion José Raúl Capablanca. It incorporates two new pieces and is played on a 10×8 board. Capablanca believed that chess would be played out i ...

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 or search may refer to: Computing technology * Search algorithm, including keyword search ** :Search algorithms * Search and optimization for problem solving in artificial intelligence * Search engine technology, software for findi ...

: 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 inc ...

, Null-move Forward

Pruning Pruning is a horticultural, arboricultural, and silvicultural practice involving the selective removal of certain parts of a plant, such as branches, buds, or roots. The practice entails the ''targeted'' removal of diseased, damaged, dead, ...

, 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 Checks'' (episode), a 1996 TV episode of ''Seinfeld'' Games and sports * Check (chess), a thr ...

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

Heuristic A heuristic (; ), or heuristic technique, is any approach to problem solving or self-discovery that employs a practical method that is not guaranteed to be optimal, perfect, or rational, but is nevertheless sufficient for reaching an immediate, ...

, Killer-move heuristic. * Evaluation:

Piece Piece or Pieces (not to be confused with peace) may refer to: Arts, entertainment, and media Games * Piece (chess), pieces deployed on a chessboard for playing the game of chess * ''Pieces'' (video game), a 1994 puzzle game for the Super NES * P ...

-square tables,

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

structure evaluation, Mobility evaluation,

King King is the title given to a male monarch in a variety of contexts. The female equivalent is queen, which title is also given to the consort of a king. *In the context of prehistory, antiquity and contemporary indigenous peoples, the tit ...

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 until its value is needed (non-strict evaluation) and which also avoids repeated evaluations (sharing). The b ...

. *

Hash Tables In computing, a hash table, also known as hash map, is a data structure that implements an associative array or dictionary. It is an abstract data type that maps keys to values. A hash table uses a hash function to compute an ''index'', als ...

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: Places United States * Cache, Idaho, an unincorporated community * Cache, Illinois, an unincorporated community * Cache, Oklahoma, a city in Comanche County * Cache, Utah, Cache County, Utah * Cache Count ...

, 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 Alice chess is a chess variant invented in 1953 by V. R. Parton which employs two chessboards rather than one, and a slight (but significant) alteration to the standard rules of chess. The game is named after the main character "Alice" in Lewis C ...

, Almost Chess, Archchess,

Berolina Chess Berolina chess is a chess variant using a popular fairy chess piece called the Berolina pawn (also known as ''Berlin pawn'', ''Anti-pawn'', or simply ''Berolina''). The Berolina pawn was invented by Edmund Nebermann in 1926''Funkschach'', August ...

, 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 Courier chess is a chess variant that dates from the 12th century and was popular for at least 600 years. It was a part of the slow evolution towards modern chess from Medieval Chess. Medieval rules Courier chess is played on an 8x12 board (i. ...

Cylindrical Chess Cylinder chess (or cylindrical chess) is a chess variant. The game is played as if the board were a cylinder, with the left side of the board joined to the right side. Cylinder chess is one of six chess variants described by the Arabic historian ...

, Diagonal Chess, Diamond Chess, Doublemove chess,

Embassy 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''. * The ...

, Eurasian Chess, Extinction Chess, Fischer Random Chess (Chess960), Great Chess, Great Shatranj,

, Grotesque Chess,

Janus Chess Janus Chess is a chess variant invented in 1978 by Werner Schöndorf from Bildstock, Germany. It is played on a 10×8 board and features a fairy chess piece, the '' janus'', with the combined moves of a bishop and a knight. The janus piece is n ...

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 chessAnderson (1986), p. 105) 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 Lab ...

Makruk ''Makruk'' ( th, หมากรุก; ; ), or Thai chess, is a 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 va ...

, Omega Chess, Opulent Chess, Roman Chess, Royal Court,

Shatranj Shatranj ( ar, شطرنج; fa, شترنج; from Middle Persian ''chatrang'' ) is an old form of chess, as played in the Sasanian Empire. Its origins are in the Indian game of chaturaṅga. Modern chess gradually developed from this game, as i ...

, Shatranj Kamil, Sosarian Chess, Switching Chess, TenCubed Chess,

Three Checks Chess This is a list of chess variants. Many thousands of variants exist. The 2007 catalogue ''The Encyclopedia of Chess Variants'' estimates that there are well over 2,000, and many more were considered too trivial for inclusion in the catalogue. ...

, and more infamous variants. Since ChessV can be programmed to play additional variants, here are a few examples: * Almost Chess, Enep, Butterfly Chess, Nightrider 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