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.
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.
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.
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.
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 unorthodox chess problems, known as fairy chess. 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.
Martian Chess is an abstract strategy game for two or four players invented by Andrew Looney in 1999. It is played with Icehouse pyramids on a chessboard. To play with a number of players other than two or four, a non-Euclidean surface can be tiled to produce a board of the required size, allowing up to six players.
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 named after the Roman god Janus because this god was usually depicted with two faces looking in opposite directions.
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.
Four-player chess is a family of chess variants played with four people. The game features a special board typically made of a standard 8×8 square, with 3 rows of 8 cells each extending from each side, and requires two sets of differently colored pieces. The rules are similar to, but not the same as, regular chess. There are a variety of different rule variations; most variations, however, share a somewhat similar board and piece setup.
Pocket mutation chess is a chess variant invented by Mike Nelson in 2003.
Three-player chess is a family of chess variants specially designed for three players. Many variations of three-player chess have been devised. They usually use a non-standard board, for example, a hexagonal or three-sided board that connects the center cells in a special way. The three armies are differentiated usually by color, with White, Black, and Red serving as the most common color combination.
2000 A.D. is a chess variant created by V. R. Parton which employs fairy chess pieces on a 10×10 board. Parton published the variant in his 1972 monograph My Game for 2000 A.D. and After.
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.
Dragonfly is a chess variant invented by Christian Freeling in 1983. There are no queens, and a captured bishop, knight, or rook becomes the property of the capturer, who may play it as their own on a turn to any open square. The board is 7×7 squares, or alternatively a 61-cell hexagon with two additional pawns per side.
Three-man chess is a chess variant for three players invented by George R. Dekle Sr. in 1984. The game is played on a hexagonal board comprising 96 quadrilateral cells. Each player controls a standard army of chess pieces.
Beirut chess is a chess variant invented by Jim Winslow in 1992. The game is played using the standard chess pieces and board, with each side having secretly equipped one of their men with a "bomb"—which can be "detonated" at any time, wiping out all men on surrounding squares along with the bomb carrier.
Falcon–hunter chess is a chess variant invented by Karl Schultz in 1943, employing the two fairy chess pieces falcon and hunter. The game takes several forms, including variations hunter chess and decimal falcon–hunter chess added in the 1950s.
