Kriegspiel (chess) follows. The game is played with three boards, one for each player; the third is for the umpire (and spectators). Each opponent knows the exact position of just their pieces, and does not know where the opponent's pieces are (but can keep track of how many there are). Only the umpire knows the position of the game. The game proceeds in the following way: The umpire announces: Pawn promotions are not announced. Kriegspiel is sometimes used in chess problems. In these, usual variations introduced by different black moves are replaced by variations introduced by different announcements. An example of a
Hostage Chess It was published in magazines "Nost-algia" (issue 375), "Eteroscacco" (86–88), and "Variant Chess" (32 and later). It was the "Recognized Variant of the Month" in January 2005 at "The Chess Variant Pages". The inventor, John Leslie, is also a philosopher. He mentions in his book "Infinite Minds" that the prevalence of chess variant inventions such as Hostage Chess has led to speculation that there could be infinite possible variations of chess. He contends these will necessarily exceed the capacity of the human mind. Hostage Chess follows all the standard rules of chess excepting how captured men are treated. Each player