by Karl Fischer
This variant of Torus Chess uses a unique setup to allow play to begin immediately on a standard eight by eight chess board, with good protection for all pieces.
I was introduced to cylindrical and torus chess in 1969 by a Methodist minister who enjoyed chess variants. His solution to the problem of the normal setup leaving both sides' pieces back-to-back on a torus board was to play a game that began with ten moves of "normal" chess without torus properties, and then change over to torus play after the tenth move. When my father beat me in a game in fewer than ten moves, I was highly motivated to find a starting setup in which torus play could begin immediately. I found that the position shown below provided great protection for all pieces during torus play, while still allowing strong lines of attack.
Using this position, the game starts, and the rules of orthodox chess apply. The chess board's edges are assumed to be joined. The sides are joined together as if they were a tube, and the front and back edges are joined as if that tube were stretched around to form a doughnut shape. Movement off of one edge or end of the board and onto the other is allowed. Promotion of pawns occurs on the normal (first or eighth) row. Exceptions to normal play are that the pawns to the sides of the king and queen can only advance one space on their first move, and that there is no castling. Also, a piece cannot move eight squares and return to its original starting square and be considered to have moved. It must alter its and the board's overall position.
Orthogonal moves - when a piece moves off one edge of the board, merely place it at the other end of the same row and continue its movement. A knight's moves are best visualized as orthogonal (up two, over one); to keep from missing some of the places it can move to or threaten.
> A tricky move with the knight starts from its normal starting square, say g1. Moving through h1 to a1, it can then make the orthogonal move to a8, potentially taking a rook!
> Note that in the starting setup, the rooks protect each other, while being threatened by the opponent's rooks. They are supported by the knights on the sides of the board, making their positions more defensible.
Diagonal moves - continue moving a piece diagonally off the edge of the board, into the next (imaginary) diagonal square ahead of it. Move the piece to the square on the other end of that same row, and continue the diagonal move, paralleling the piece's original direction. If you've done the move right, its extended path would return a bishop or queen to its original position. Moving off one end the long diagonals a1-h8 or h1-a8 will cause the piece to reappear on the other end of the same long diagonal, still paralleling the move's original direction.
> Watch out for diagonal attacks from pawns positioned on the side of the board.
> Note that the queens threaten the rooks at a1 and a8, making the rooks on that side of the board slightly less secure than the king's side rooks.
Sample endgame mate: 1. Black to move ... Kd6 2. Qe5#. (If white was to move first, there would be a mate in one move with Qe7. Other less powerful pieces could have protected the queen on e7, showing the way to make similar checkmates without a rook. With the rook and the first move, Qe5, Qg6, or Qh6 would also result in a mate.)
Final position (the queen covers the rook on the diagonal passing through h2, a1, and b8).
1. Nh3-g1, Na6-h4 2. Ng1xa8, Rh8xh1 3. Na3xh1, Bf8-g1+ 4. Nh1-f2, Qd6xa1 5. Bf1xh7, Bg1-f8 6. Na8xh6, Nh4-g2#