The Economist has an interesting article on the world’s largest city:

Tokyo is now the world’s largest city, with 37m residents in the metropolitan area and 14m in the city proper. It is also one of the world’s most liveable, with punctual public transport, safe neighbourhoods, clean streets and more restaurants and Michelin stars than any other. In the liveability index of the Economist Intelligence Unit, our sister group, Tokyo comes joint fourth, but its population is larger than the combined populations of the others (Adelaide, Auckland, Osaka and Wellington). “It’s possible to have a liveable city at any scale—Tokyo proves that,” says Gabriel Metcalf, at Committee for Sydney, an Australian think-tank.

The article discusses the role of planning:

Tokyo’s liveability is a product of planning’s successes but also its failures, argues Jordan Sand of Georgetown University. One success was public transport. After the Meiji restoration, the government put rail ahead of roads, expanding networks through the city and then underground. Even as large firms in America built headquarters in suburbs, in Japan they clustered around transport hubs, incentivising the use of trains and subways, says Okata Junichiro of the University of Tokyo. That helped make Tokyo polycentric, with many hubs, not one.

What the article doesn’t say is that the transit system is surprisingly decentralized.  While Tokyo’s largest operator (JR East) is government owned, the metro area is served by 48 different commuter rail operators.  Of the 158 rail lines in the Tokyo area, no fewer than 55 are run by private operators.  

You may recall that Japan’s postwar boom occurred partly because firms like Honda ignored the diktats of government planners (who wanted them to stick to motorcycles.)  Something similar happened with urban planning:

Around those hubs grew dense, mixed-use neighbourhoods. That was the planning “failure”. After the war, city planners sought to impose zoning as in the West, as they had after the Great Kanto Earthquake of 1923. But the government’s resources were too limited and Tokyo’s growth too rapid to control the process. Japan instead developed lax zoning codes, which allow pretty much anything to be built, rather than prescribing what is permitted. Historically, this model “was part of a modernist ethos to separate functions, to say work happens here, living happens here”, explains Mohsen Mostafavi of Harvard’s Graduate School of Design.

For those interested in urban planning, I found this video on Tokyo’s lax zoning rules to be quite interesting: