Dr. B's Stolen Chess Book in Isolation
Dr. B, a Viennese lawyer held by the Gestapo in an empty hotel room, steals a book of 150 master games and memorizes them to escape the void, then begins playing against himself in his head as a White self and a Black self until this 'chess poisoning' ends in a breakdown. Some weeks after his release, on an ocean liner, he beats the world champion Czentovic in one game. In the second he starts to lose himself again and stops when the narrator warns him.