It stirs to life when the high-rise office lights click off floor by floor, when bleary-eyed men in suits drift away to their homes in the suburbs and beyond. It simmers with activity even as the most garrulous crows snooze beneath the stars.

Nighttime Tokyo. Same boulevards and parks, same ferroconcrete jumble -- and yet, so different from the teeming metropolis we see by day.

It's a world apart, largely unknown to the millions who crowd it by day, but who -- like legions of salaried Cinderellas -- seldom stay past the stroke of midnight when commuter lines and bus services start closing down.