Japan is about one-twenty-fifth the size of the United States —slightly smaller than California —but it contains about one-half the population of the United States. The country is three times more densely populated than Europe and about twelve times more densely populated than the United States. And since the interiors of the islands are mostly dominated by mountains, nearly 30 percent of the people in Japan crowd into the Tokyo region.

Navigating through this vast expanse of humanity is a daunting task for even the most experienced travelers. Because of its ancient roots as a military fort, Tokyo is notorious for its winding streets, narrow alleys, and confusing street grid. Although the city sprawls over eight hundred square miles, few of the streets even have names. Fusillo and Araki explain why:

Tokyo began as a castle town, and castle towns are notoriously difficult to navigate...