Tri-Cubic Chess is a 72 square variant where three cubes each 2×2×6 are arranged vertically one on top of the other through opposing cube corners. Pieces are orthodox minus pawns and arranged on outer cubes at top and bottom rows. Pawns are not required and would be far too complicated to include so all pieces can retrieve taken pieces upon reaching the opponents sides of the board
This shows the diagonal movements of queen and bishop. Diagonal movement can be an endless loop around one cube, whereas from one cube to another is restricted and movement from one cube to another can only be diagonally. The diagonal movement of the queen to the upper cube has the option of going to one of both sides. The bishop shows an endless diagonal loop in one move while the other move is restricted to two squares.
This image shows the board rotated 180 degrees and how rooks and knights can move around the board. The rooks can also move around the board in the other directions towards the other rook and knights. Note how square color is reversed to the King, Queen and Bishops sides so diagonal movement between cubes can be via red squares as well allowing both players bishops to move to all cubes. Rooks are restricted to their base cube and cannot move to the middle cube because movement to the middle cube can only be diagonally.
Written by Robert Bell.