Japan's orderly Shibuya Scramble

Then, on cue, the pedestrian masses on the four corners surged forward. Seen from above, they were great armies entering battle, each moving with determination toward their point of contact.

But there was no clash. In the middle, they came together in fluid movement, like cards shuffled in the hands of a Vegas dealer, each sliding seamlessly past the other.

For nearly a full minute, the intersection was a sea of humanity. Slowly, the crush trickled out and the asphalt was again almost empty, only a few stragglers rushing to beat the light.

Then it reverted to the throb of vehicle traffic, another cycle of Shibuya synchronicity complete.

"It's an unrehearsed choreography," said Tsuyoshi Yamada, an unofficial expert on the history and idiosyncrasies of the crosswalk. "It's a dance."

Twice each weekday, on his way to work and home again, Yamada negotiates the intersection, perhaps the most peopled and yet most orderly one on the planet.

It's known as the Scramble, and for good reason.

The crossing, a 10-lane traffic interchange half the size of a football field, is in the heart of the youth-dominated Shibuya, a barometer of this city's edgy teen culture with its ever-shifting fashions and often-wacky trends. At its rush-hour height, the Scramble is flooded by 2,500 pedestrians — some pink-haired and nose-pierced, others in conservative skirts or suits — with a single change of a traffic signal.

But in this polite nation, the passing bodies seem less chaotic than in, say, Beijing or New York, moving with the cool predictability of a stopwatch. Despite so much humanity inhabiting such a confined space, there's rarely a collision, sharp elbow, shoulder-brush or unkind word.

For Yamada, 64, a white-haired veteran in the Shibuya district government office, the Scramble is something of a singular calling: He's a student of the crossing's place in Japanese culture, likening its ballet to North Korea's Mass Games, in which thousands of gymnasts take part in a spectacle of rhythm and order.

"It's more than just a feat of engineering," said Yamada, a deskbound records-keeper with the title of data management officer. "It reflects the pulse of Tokyo."