Timothy and Kimothy were playing a rather intense game of Kriegspiel the other day. For those of you who don't know...
Kriegspiel is a version of chess in which the players are not allowed to see the moves of the opponent. Instead, there is a "referee" who keeps track of the each move on his own private board and tells the players if an attempted move is legal. If an attempted move is legal, the player must play it; otherwise, the player may try again. In addition, the referee announces all captures and whether the captured object is a piece or a pawn. In the RAND rules, the referee also announces checks, and possible captures by a pawn.
Blind Uncle Jimothy seemed to quite enjoy listening to them to play. Which led me to wonder...
Can a blind person, hearing only the announcements of the referee, deduce a mate for one of the players?
A referee would say "No" following an attempt by a player to make a move that appears legal only taking into consideration his pieces on his own board, but is in fact illegal according to the actual position as seen by the referee.
The RAND rules, consider this stricter definition of a ``No'' to be in force if the present announcement is a check of some sort.
(Note: This is not an original puzzle, It comes from UCLA professor Tom Ferguson's web page)