Baroque chess is a chess variant invented in 1962 by Robert Abbott. In 1963, at the suggestion of his publisher, he changed the name to Ultima, by which name it is also known. Abbott later considered his invention flawed and suggested amendments to the rules, but these suggestions have been substantially ignored by the gaming community, which continues to play by the 1962 rules. Since the rules for Baroque were first laid down in 1962, some regional variation has arisen, causing the game to diverge from Ultima.
The pawn is the most numerous and weakest piece in the game of chess. It may move one square directly forward, it may move two squares directly forward on its first move, and it may capture one square diagonally forward. Each player begins a game with eight pawns, one on each square of their second rank. The white pawns start on a2 through h2; the black pawns start on a7 through h7.
Losing chess is one of the most popular chess variants. The objective of each player is to lose all of their pieces or be stalemated, that is, a misère version. In some variations, a player may also win by checkmating or by being checkmated.
Circe chess is a chess variant in which captured pieces are reborn on their starting positions as soon as they are captured. The game was invented by French composer Pierre Monréal in 1967 and the rules of Circe chess were first detailed by Monréal and Jean-Pierre Boyer in an article in Problème, 1968.
Monster chess—or Super King chess—is a chess variant in which the White side has only a king and four pawns to fight against all the pieces of the Black side. All the rules of chess apply, except that White makes two successive moves per turn. The white king can move into check on the first move of the turn and move out of check during the second move. The goal for both sides is to checkmate the opponent's king.
Alice chess is a chess variant invented in 1953 by V. R. Parton which employs two chessboards rather than one, and a slight alteration to the standard rules of chess. The game is named after the main character "Alice" in Lewis Carroll's work Through the Looking-Glass, where transport through the mirror into an alternative world is portrayed on the chessboards by the after-move transfer of chess pieces between boards A and B.
A fairy chess piece, variant chess piece, unorthodox chess piece, or heterodox chess piece is a chess piece not used in conventional chess but incorporated into certain chess variants and some chess problems. Compared to conventional pieces, fairy pieces vary mostly in the way they move, but they may also follow special rules for capturing, promotions, etc. Because of the distributed and uncoordinated nature of unorthodox chess development, the same piece can have different names, and different pieces can have the same name in various contexts as it can be noted in the list of fairy chess pieces.
Progressive chess is a chess variant in which players, rather than just making one move per turn, play progressively longer series of moves. The game starts with White making one move, then Black makes two consecutive moves, White replies with three, Black makes four and so on. Progressive chess can be combined with other variants; for example, when Circe chess is played as a game, it is usually progressively. Progressive chess is considered particularly apt for playing correspondence chess using mail or some other slow medium, because of the relatively small number of moves in a typical game.
In chess problems, retrograde analysis is a technique employed to determine which moves were played leading up to a given position. While this technique is rarely needed for solving ordinary chess problems, there is a whole subgenre of chess problems in which it is an important part; such problems are known as retros.
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 opponent. In other words, the objective is any of the following:
Tamerlane chess is a medieval chess variant. Like modern chess, it is derived from shatranj. It was developed in Central Asia during the reign of Emperor Timur, and its invention is also attributed to him. Because Tamerlane chess is a larger variant of chaturanga, it is also called Shatranj Al-Kabir, as opposed to Shatranj as-saghir. Although the game is similar to modern chess, it is distinctive in that there are varieties of pawn, each of which promotes in its own way.
Kriegspiel is a chess variant invented by Henry Michael Temple in 1899 and based upon the original Kriegsspiel developed by Georg von Reiswitz in 1812. In this game, each player can see their own pieces but not those of their opponent. For this reason, it is necessary to have a third person act as an umpire, with full information about the progress of the game. Players attempt to move on their turns, and the umpire declares their attempts 'legal' or 'illegal'. If the move is illegal, the player tries again; if it is legal, that move stands. Each player is given information about checks and captures. They may also ask the umpire if there are any legal captures with a pawn. Since the position of the opponent's pieces is unknown, Kriegspiel is a game of imperfect information.
Knight relay chess is a chess variant invented by Mannis Charosh in 1972. In this game, knights relay their power to friendly pieces.
Hexagonal chess is a group of chess variants played on boards composed of hexagon cells. The best known is Gliński's variant, played on a symmetric 91-cell hexagonal board.
Legan chess is a chess variant invented by L. Legan in 1913. It differs from standard chess by the starting position as well as by pawn movements.
Monochromatic chess is a chess variant with unknown origin. The initial board position and all rules are the same as in regular chess, except that pieces that begin on a black square must always stay on a black square and pieces that begin on a white square must always stay on a white square. This would mean that knights can never move, but The Classified Encyclopedia of Chess Variants says that knights make a double jump. It has been suggested that a knight be replaced with a (3,1)-leaper (camel).
Wildebeest chess is a chess variant created by R. Wayne Schmittberger in 1987. The Wildebeest board is 11×10 squares. Besides the standard chess pieces, each side has two camels and one "wildebeest" - a piece which may move as either a camel or a knight.
Hostage chess is a chess variant invented by John A. Leslie in 1997. Captured pieces are not eliminated from the game but can reenter active play through drops, similar to shogi. Unlike shogi, the piece a player may drop is one of their own pieces previously captured by the opponent. In exchange, the player returns a previously captured enemy piece which the opponent may drop on a future turn. This is the characteristic feature of the game.
Dynamo chess is a chess variant invented by chess problemists Hans Klüver and Peter Kahl in 1968. The invention was inspired by the closely related variant push chess, invented by Fred Galvin in 1967. The pieces, board, and starting position of Dynamo chess are the same as in orthodox chess, but captures are eliminated and enemy pieces are instead "pushed" or "pulled" off the board. On any given move, a player can make a standard move as in orthodox chess, or execute a "push move" or a "pull move". A move that is either a push move or a pull move is called a "dynamo move".
