Tokyo's Secret Underground City

"What changed his life was finding an old map in a secondhand bookstore. Comparing it to a contemporary map, he found significant variations. 'Close to the Diet in Nagata-cho, current maps show two subways crossing. In the old map, they are parallel.' The journalist in him taking over, he sought out construction records. When responses proved defensive and noncooperative -- 'lips zipped tight' -- he set out to prove that the two subway tunnels could not cross: 'Engineering cannot lie.'.. This inconsistency is just the first of seven riddles that he investigates in his book. The second reveals a secret underground complex between Kokkai-gijidomae and the prime minister's residence."