Many consider Chiyoda the heart of Tokyo, and no wonder. The ward pumps lifeblood in and out with circadian regularity.

During working hours, Chiyoda's population swells to an estimated 850,000 people who pulse through the business arteries of Yurakucho, Marunouchi, and Akihabara. By midnight, the place empties and a mere 40,000 or so are left catching their Zs here. No other ward approaches this degree of flux.

"Chiyoda would like to increase its number of residents, to boost income from real estate and individual taxes," says Shoko Matsumura, 23-year resident of the ward and chief manager of Matsumura Kaikei Jimusho, a tax accounting office in Kudankita. "The problem is Chiyoda's very expensive, and even with the nice parks, there are so many tall buildings that sometimes I feel I can only see a tiny piece of the sky."