The Chess Variant Pages




Spacious Torus Chess

The Problem

To play torus Chess[1] on the 8x8 board always being problematic. It is obviously impossible with FIDE rules, for the kings start in mutual check position. For a minimalist (at least for this variant) like me, changing the openning setup in any drastic way just doesn't quite appeal to me. But that left me stuck ...

Toward the Solution

first insight

...Until I read Ralph Betza's article on spacious pieces. Then it occured to me if the pieces were all spacious FIDEs then the kings would not be in mutual check since they can't make any spacious captures for to do so requires a open square beyond the captured piece which is blocked by the pawn. In fact for similar reasoning all pieces except the pawns on the A, C, F, and H files are safe. Another look would prove A, C, H file pawns are safe too, for they are protected by Rook, Queen, and Rook respectively.

a refinement

So I'm very close to what I want, a minimalistic 8x8 torus chess variant. However there's one blemish, the F file pawns [2]. Since they can be taken by the knight on g1 (made possible by the empty square on e5). The king is no help, since if it captured the invading knight, it would be moving into check from the queen at d1.

To solve this problem, The following diagram illustrates this:

RBQKBR
PPPPPPPP
NN


NN
PPPPPPPP
RNBQKR

Null Moves

Because the board is a torus, it is possible for a piece to travel around it and end up at the starting square. This have to be barred from the game to keep the players from perpetuating null moves.

The Rules

Spacious Torus Chess is played as FIDE except for otherwise listed below.

1. The board is a torus, i.e. Rank 1 and Rank 8 is adjacent, and file a and file h is adjacent.

2. All the pieces are spacious FIDE pieces and requires the next square beyond to be empty to either move or capture.

3. The starting configration is as follows:

RBQKBR
PPPPPPPP
NN


NN
PPPPPPPP
RNBQKR

4. No null moves allowed, such as moving the rook from one square around the board and back to the same square it started from.

Notes

It is easier to visualize games played on torus boards by viewing the game from two different perspectives. To this end, the following is the starting position from another point of view.


NN
PPPPPPPP
KBRRBQ
KBRRBQ
PPPPPPPP
NN

Strategy

Like checkers, this game starts in a very unstable position, and slight differences in move choices in the first ten moves can drastically alter the balance of power. So one should try the utmost to maintain balance and not be tempted to capture unnessarily, for it might lead to move combinations that might pull you under.

Variants

Due to the higher draw margin, it is recommended that advanced players play with Renormalized Rules as stated by Kevin Maroney here Refer to the first three rules of Ur Chess. These are:

  1. A player who cannot make a legal move loses
  2. A player who is reduced to only a king loses
  3. No player may repeat a previous board position

Zillions

The zillions file shows two boards. The right one is for visualization only and echos the moves made on the left.

spacioustorus.zip

Checkmates are not recognized propely in my zillions file, but it will anounce a win. Any suggestion on a patch appreciated.

acknowledgement

[1] Torus Chess is played on a torus. In this incidence that means 1st and 8th rank are glued together, and a and h files are glued together. For more info take a look at Gadsden's Toroidal Chess

[2] thanks to Ralph Betza for spotting this line of reasonning and for the encouragement to submit this article. For more info click here [3] Thanks to David Howe's Alfaerie collection


Written by Jianying Ji.
WWW page created: Nov. 11, 2001.