Rollerball (chess variant)

Rollerball is a chess variant invented by Jean-Louis Cazaux in 1998. The game was inspired by the 1975 science-fiction movie "Rollerball", specifically the futuristic and violent sport (similar to Roller Derby) portrayed in the film.
The board comprises 7×7 squares with the central 3×3 section missing. Pieces generally move clockwise around the board. Each player starts with one king, one bishop, two rooks, and two pawns. Both bishops are light-squared, and dark-squared bishops can only be obtained by pawn promotion.
Game rules.
The initial setup is as shown. White moves first. Pieces move and capture the same as their chess counterparts, except where explained differently below.
Objective.
There are two ways to win in Rollerball:
The same as in chess, stalemate and threefold repetition of position are draws.
Piece moves.
In general, "forward" movement means clockwise direction around the board; "backward" movement means counterclockwise direction. The squares comprising the board's inner and outer perimeters are called "rings". The ring a rook or pawn currently stands on determines its orthogonal forward direction, and for a rook, its orthogonal backward direction. An orthogonal rook move in a direction immediately off its ring is called "sideways" movement.
References.
Bibliography