Fortress chess

Fortress chess is a four-player chess variant, played in two teams of two, that developed in Russia during the eighteenth and nineteenth centuries. The earliest suggested reference to the game comes from William Coxe's 1784 travel writing, and family recollection recorded by the chess player Alexander Petrov held that Catherine the Great had played a version of it. The first confirmed modern description of the rules was published in 1821 by Ivan Alexandrovich Butrimov, and Alexander Petrov later clarified the rules further in the German chess periodical Schachzeitung. The game is played on an enlarged board of 192 squares that includes a fortress area in each corner, in which each player sets up extra knights, bishops and rooks before play begins. Teammates sit opposite one another and the four players move in turn around the board in a clockwise order, combining their forces against the opposing team. A game ends once both members of one team have been checkmated, so cooperation between partners is as important as individual tactics.