Sideways Pawns is exactly like regular chess, except for one thing: the pawn has the ability to move one square to the side into an unoccupied square.
Thus, pawns can move forward or sideways, or capture on the forward diagonal. En Passant, promotion, and the optional two-square advance from the starting rank are unchanged from regular chess.
This variant presents opportunities for blocking check, creating forks, enabling revealed attacks, and provoking mayhem not available in regular chess!