ChessV (short for Chess Variants) is a free

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

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 dist ...

. ''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 anno ...

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: 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 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 * ...

-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 regnant, queen, which title is also given to the queen consort, consort of a king. *In the context of prehistory, antiquity and contempora ...

safety, King tropism, Lazy evaluation. *

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'', ...

: Transposition table, Pawn structure table, Evaluation cache, 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 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,

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, Eurasian Chess,

Extinction Chess Extinction chess is a chess variant invented by R. Wayne Schmittberger, editor of '' Games'' magazine, in 1985. Instead of checkmate as the winning condition, the object of the game is the elimination of all of a particular type of piece of the o ...

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

, Grotesque Chess, Janus Chess, Kinglet, 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 Labora ...

, Makruk, Omega Chess, Opulent Chess, Roman Chess, Royal Court, Shatranj, 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 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