Each player begins the game with one Wall piece, in addition to their normal pieces. The Wall begins the game off of the board. Instead of moving a piece on the board, a player may place their Wall on any unoccupied space on the board. The Wall cannot be captured. The Wall blocks all movement through the space it occupies, including Knights (i.e. a Knight cannot jump a Wall).
Once a Wall has been placed, it cannot be removed from the board. However, the player may, instead of moving a piece, take their Wall and again place it on any unoccupied space on the board. Once the Wall has been placed, it may not be moved for one full turn.
Example: In turn 3, Player 1 places his Wall piece on the board. Player 1 will be unable to re-place his Wall until Turn 5.