Chess on a torus

8 × 8 variant (standard pieces)

For a torus, opposing edges of the board are glued to each other.

In order to avoid putting both kings in check in the initial position, a different starting position has been suggested.

8 × 8 variant (modified pawns)

Also here the board is the same as for the previous variant.

This version uses a different starting position, there is no castling, pawns step orthogonally in any direction or capture diagonally in any direction and are not promoted.

8 × 14 variant

This variant uses a larger board with a more standard starting position.

Here the pieces of each player are flanked by a line of pawns on either side. Pawns always move away from their friendly pieces towards the opponent, where they are promoted.

8 × 16 variant

This variant uses an even larger board.

Here not only pawns are doubled, but also other pieces, except for the king. As an extra piece, the general (knight + queen) is introduced. Pawns always move away from their friendly pieces towards the opponent, where they are promoted.