José Raúl Capablanca in the context of Juan Corzo

A chess variant is any board game related to, derived from, or inspired by orthodox chess. Chess variants can differ from standard chess in many different ways, including variant board sizes, non-standard fairy pieces, alternative starting positions, and additional rules. There are thousands of known chess variants (see list of chess variants). The Classified Encyclopedia of Chess Variants catalogues around two thousand, with the preface noting that—since creating a chess variant is relatively easy—many were considered insufficiently notable for inclusion. While most chess variants are not widely played, some have reached modest levels of popularity, with the most successful being Chess960. Several well known modern chess masters like Capablanca, Fischer, and Yasser Seirewan developed their own chess variants.

"Classical", "orthodox" or "Western" chess itself is one of a family of games which have related origins and could be considered part of the same board game family. Modern chess itself developed from the Indian chaturanga via the Middle-eastern shatranj. During the Middle Ages, there were numerous popular chess variants, like Great chess and Courier chess. Modern chess variants are mostly all variations on standard Western chess. Though not technically variants of modern chess, there are also many regional games which are part of the same family, such as shogi (Japan), sittuyin (Burma), makruk (Thailand), hiashatar (Mongolia), and xiangqi (China). These games have their own history of variants (see shogi variants and xianqi variants).