KoeKo: A move is possible only if the piece moved arrives on a square next to another unit.

GridСhess: The board is divided not only into its usual 64 squares, but also into 16 larger squares consisting of 4 normal squares each. All moves by both sides must cross at least one line of the grid. Illegal are all settings with white or black King on the squares ‘a1’, ‘h1’, ‘a8’ and ‘h8’.

Nightrider (N): Operates along straight lines with squares lying a Knight`s move away from each other.