Rollerball (chess variant)

Rollerball is a chess variant invented by Jean-Louis Cazaux in 1998, taking its name and theme from the 1975 science fiction film Rollerball, which depicted a violent future sport resembling roller derby. The board departs sharply from standard chess: it is built from a seven by seven grid with the central three by three block of squares removed, leaving a hollow ring of playing squares around an empty core. Each side begins with a reduced army of one king, one bishop, two rooks, and two pawns, with both starting bishops on light squares; a dark-squared bishop can only appear later through pawn promotion. Movement follows the ring itself: pieces generally travel clockwise around the loop for forward moves and counterclockwise for backward moves, and both the rook and the bishop can rebound once off a corner or edge of the ring rather than simply stopping. A game can be won in either of two ways, by delivering checkmate in the traditional sense, or by successfully moving one's own king all the way around the ring, clockwise, to occupy the opponent's starting square. The variant otherwise keeps standard chess draw conditions such as stalemate and threefold repetition.