RAND Staffers Playing Blind Chess

RAND staffers playing blind chess on a break.  Players can see the position of only their own pieces, and an umpire tells them whether attempted moves are legal or not.  This chess variant is also known as Kriegspiel, based on a mode of tabletop war games developed by the Prussian army in the 19th century that were precursors for wargaming techniques developed and played at RAND and elsewhere.  Kriegsspiel is the German word for wargame.  Image courtesy of the RAND Archives.