invented by Don Miller in 1965 - modified by Leo Nadvorney in 1972
- The board is spherical:
- A rook moving through a pole emerges on the opposite side and continues in a straight line, as for example Ra3-a1-e1-e4.
- Bishop moving through the pole from a given square emerges one square away from the diametrically opposite one, depending on which direction it is moving. Examples are Bh3-g2-f1-a1-h2-g3 and Bd3-e2-f1-c1-d2-e3, but not Bh3-g2-f1-c1.
- Moves of other pieces can be inferred from the above; for example, a knight move can be regarded as a 1-step R move followed by a 1-step B move, such as Sd1-h1-g2/a2.
- Since are no edges, pieces can move around the board along the ranks
as in Cylindrical Chess.
This requires two ruling like those for Cylindrical Chess:
- A piece may not make a move around the board (like Rh3-a3-h3) that leaves the position unchanged, nor may it make an infinite (never ending) move.
- Two new forms of castling are possible, if the usual condition are fulfilled: Ka1-c1, Rh1-d1 over a1 (written C0-0-0) and Ke1-g1, Ra1-f1 over h1 (written C0-0).
The Laws of Chess apply, except as follows:
On transpolar moves it may make things clearer to indicate the square from which the pole was crossed, but this is not necessary.
Written by: Alessandro Castelli (email removed contact us for address) ink.it
WWW page created: September 30, 1996. Last modified: October 10, 1996.