This frame is based on V.R. Parton's chess variant Alice Chess.

Place two boards for the same board game side by side. Set up the first board normally. Leave the second board, called the mirror board, empty.

Call the piece a space would normally land on when it makes a particular move its target. Call the space on one board that corresponds to a space on the other board its mirror space. There are three rules of movement.

  1. A move must be legal on the board where you make it.
  2. When a piece moves, it travels “through the looking-glass” and lands on its target's mirror space.
  3. Therefore, in order for a piece to move, its target's mirror space must be empty.