I have recently seen a documentary that showed how precious is the space in Japan's large cities (example).

This places the largest cities in Japan (Osaka, Tokyo) within the top cities when it comes to apartments prices, population density, and rental affordability.

Indeed Japan uses high tech to tackle lack of space very efficiently, but it seems that population density is quite high.

Question: why does Japan concentrate so much population in just a few very large cities?

As mentioned in the comments, there are many factors that influenced this. However, I am interested in the political factors/decisions that favored this kind of city developing.

  • There is a massive anthropological study that could be done on why Japan has such massive population concentration. I've voted to close this as too broad, because as it is currently scoped it would include factors and influences that are outside of the topic areas for this SE. Oct 13, 2017 at 16:07
  • @DrunkCynic - Yes, this is true. I am interested only in the political decisions that influenced this course of development, so that the answers make sense on Politics.SE. I will try to edit the question to narrow its scope.
    – Alexei
    Oct 13, 2017 at 16:08
  • 4
    this isn't a japanese thing as much as it is a modern human thing. large cities keep getting larger everywhere.
    – user1530
    Oct 13, 2017 at 16:26
  • @blip - "modern"? Rome had insanely high (for its time and agricultural economy efficiency) ratio of 40% city dwellers in some provinces (Carthage if memory serves).
    – user4012
    Oct 13, 2017 at 17:44
  • @user4012 well, I wasn't using 'modern' as a technical term. I suppose there's a better way to say that. Maybe "since humans invented cities" or something.
    – user1530
    Oct 13, 2017 at 17:49

3 Answers 3


Japan has a population of over 120 million, in an area of a little under 400000 km2. Compare this to California: an area of a little over 400000km2, and a population of 40 million.

So imagine tripling the population of California.

You need to build homes for all these people. You probably don't build in Yosemite or Trinity forest, because these areas are mountainous and forested. Instead you fill up the land you have in LA and in the valley, because this land is flat and easy to build upon. The result would be a population concentrated in massive, densely populated cities.

In Japan there is very limited land suitable for building: the Kanto plain, the Kansai region. These regions are highly built-up. Much of the land is mountainous, and so largely unpopulated. There are cultural factors too. The people in Japan had historically been a fishing and seafaring people, so many of the large cities were coastal (Kyoto being an obvious exception) Nowadays, there are jobs in the cities, which are close to trade links.

Hence people choose to live in the cities as there are jobs, family, and there is literally nowhere else for them to go.

  • 2
    "Much of the land is mountainous, and so largely unpopulated." That's really the key thing. Use google Earth to fly around Japan and it quickly becomes clear that the all the flat areas are heavily populated and the mountains are not. You will also note how sudden the transition from multistory buildings to no buildings is when you reach the moutains.
    – Readin
    Oct 14, 2017 at 3:41
  • This also explains why Japan isn't too worried about its population shrinking and doesn't encourage immigration to counter balance things. Oct 14, 2017 at 15:50

Japan on Wikipedia, stats:

  • Area: 377,972 km^2 (145,936 sq mi)
  • Population: 126,740,000
  • Density: 336/km^2 (870.2/sq mi)

Compare to


  • Area: 423,970 km^2 (163,696 sq mi)
  • Population: 39,250,017
  • Density: 93/km^2 (240/sq mi)

The United Kingdom:

  • Area: 242,495 km^2 (93,628 sq mi)
  • Population: 65,648,000
  • Density: 270.7/km^2 (701.1/sq mi)


  • Area: 238,397 km^2 (92,046 sq mi)
  • Population: 19,638,000
  • Density: 84.4/km^2 (218.6/sq mi)

California makes for a good comparison, as it is only a bit larger in area, with less than a third of the population. Yet most of the population of California is in the greater metropolitan areas of Los Angeles, San Jose-San Francisco-Oakland, San Diego, and Sacramento (about 33 million combined).

Or compare to Sud-Muntenia in Romania. That's the administrative division in Romania around Bucharest. If we combine Bucharest and Sud-Muntenia, we get a population density of only 149/km^2. That's less than half the population density in Japan. Yet Bucharest is easily the biggest city in Romania, much less that area. Why do Romanians squeeze themselves into just one city?

The densest "city" in Japan according to your source is Osaka/Kobe/Kyoto at 38th. Bucharest doesn't even make that list, despite having an eighth of the population of Romania in it. London makes the list at 43. Why does the UK pack itself into just a few cities? Both the UK and Japan have five cities on that list even though the UK has half the population and a lower density.

Japan has a lot of people and not that much space. Yet it's not significantly more prevalent in the highest population density list than the UK, with half the population. The actual city of Bucharest itself has a higher population density than any of the metropolitan areas listed in Japan. Yet Japan has six times the population and four times the density of Romania. California has a third as much population and still appears on the list three times (and we could get that up to five if we added Hawaii and Nevada).

I don't think that Japan is that exceptional in this area. Further, I don't think that this is really caused by political factors in Japan. The primary issue is that Japan has a lot of people and few places to put them. This leads to high density in those places that are suitable for building. Particularly as Japan is in an earthquake zone and needs to be extra careful in its building. It can't just build on the side of a mountain. This restricts it from using some of what land it does have.

  • While it is clear that Japan was forced into squeezing its population due to lack of space, for Bucharest (btw - a fairly good question, I think) there are clearly some political factors: communist era (many apartments in blocks one near the other to accommodate many workers in a relatively small area) and post-revolutionary politics which contribute next to nothing to a more uniform development of cities / areas (many counties are very far from any highway, have virtually no industry etc.). Thanks for the thorough answer.
    – Alexei
    Oct 13, 2017 at 19:20

However, I am interested in the political factors/decisions that favored this kind of city developing

An important political factor that influences how land use is regulated in Japan is that authority over land use regulation is largely at the national/regional level, rather than the local level as it is in the U.S.

This makes "not in my backyard" (NIMBY) political opposition to development much less effective.

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