Patricia is a small chess variant, invented by Rob Nierse. Specific points of the game are that pieces change every move of type, and that taken pieces can be dropped.
Also, the purpose of the game is to take the royal piece of the opponent; thus it is legal (but not desirable) to put ones king to a position that is attacked by a piece of the opponent.
An interesting question is: does this rule make it impossible to have a stalemate in Patricia? Consider that even if the royal piece is not attacked, and that all squares it can move to are under attack of a piece of the opponent, it is not necessarily a stalemate, because a move that puts a king into check is legal.
So, here is a puzzle for readers of the Chess Variant pages: show that it is possible to have a stalemate (a player whose turn it is is unable to make any legal move) in Patricia.
See the description of Patricia for the rules of the game.
Rob Nierse, inventor of Patricia, was the first to send in a solution to this problem. Congratulations, Rob!
Try to find the solution yourself, or just read
Written by: Hans Bodlaender.