List of chess variants

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.
The chess variants listed below are derived from chess by changing one or more of the many rules of the game. The rules can be grouped into categories, from the most innocuous (starting position) to the most dramatic (adding chance/randomness to the gameplay after the initial piece placement). If a variant changes rules from multiple categories, it belongs to the sub-section below corresponding to the later-listed category.
Names that represent a set of variants are annotated with "[multivariant]" after their name. All variants use an 8x8 board unless otherwise specified.
Many variants employ standard chess rules and mechanics, but vary the number of pieces, or their starting positions. In most such variants, the pawns are placed on their usual squares, but the position of other pieces is either randomly determined or selected by the players. The motivation for these variants is usually to nullify established opening knowledge. The downside of these variants is that the initial position usually has less harmony and balance than the standard chess position.
In these variants, White and Black do not necessarily begin with the same quantities of each piece type (for example, White may begin with more pawns than Black).
Most of the pieces in these variants are borrowed from chess. The game goal and rules are also very similar to those in chess; however, these variants include one or more fairy pieces which move differently from chess pieces.
There are a number of variants which use the empress (rook + knight) and princess (bishop + knight) compound pieces. The empress is also called marshall or chancellor. The princess is also called cardinal, archbishop, janus, paladin, or minister. Another compound piece is the amazon (queen + knight). To adapt to the new pieces, the board is usually extended to 10×8 or 10×10 with additional pawns added.
These variants introduce changes in the mechanics of the game, such as movement of pieces, rules for capturing, or winning conditions.
In these variants one or both players can move more than once per turn. The board and the pieces in these variants are the same as in standard chess.
These variants feature variant rules in the middle of the game, but the end goal remains the same (to checkmate the enemy king).
In this category, the movement of pieces can be modified in concurrence with the geometry of the board.
A number of variants have been developed where the playing area is in three dimensions or more. In most cases an extra spatial dimension is represented by multiple boards being laid next to each other. Some extra-dimensional variants attempt to reflect the 3D nature of modern warfare (e.g. Raumschach, designed to reflect aerial and submarine warfare), while others incorporate fantasy or science fiction ideas such as parallel worlds and time travel. An example of the latter is the variant introduced by the 2020 computer game 5D Chess with Multiverse Time Travel, which uses a varying number of boards all being played in parallel.
In contrast to standard chess, which is a game of complete information, in these variants, the players do not have perfect information about the state of the board, or there is an element of chance in how the game is played after the initial setup of pieces.
These variants are very different from chess and may be classified as abstract strategy board games instead of chess variants.
Some of these games have developed independently while others are ancestors or relatives of modern chess. The popularity of these variants may be limited to their respective places of origin (as is largely the case for shogi), or worldwide (as is the case for xiangqi). The games have their own institutions and traditions.
Bibliography
Shogi
Xiangqi
Others