Tokyo has rightly been getting some plaudits for housebuilding of late, and this post brings together some stats that illustrate just how impressive its record is.

First, some definitions and context. The statistics in this post are all for the Tokyo Metropolis area, also known as Tokyo Prefecture, with a population of around 13.5 million as of 2015. This is just part of the Greater Tokyo urban area, which holds around 37.8 million people, but for the purpose of this post when I say ‘Tokyo’ I mean the Metropolis/Prefecture.

The data in this post come from three online collections: the Tokyo Statistical Yearbook, the Japan Housing and Land Survey tables and Historical Statistics of Japan. As data sources these are all the more useful for being extremely old-fashioned: data is presented in tables using the same variable names and layouts going back decades, arranged on sites that are blessedly free of intrusive bells and whistles. Long may that continue, because when combined with an awesome commitment to publishing statistics in English, the end result is an amazingly accessible trove of historic data, probably more than is available for any other city I’ve looked at, including London.

It’s well known that Japan’s population is falling, but less so that Tokyo continues to grow, adding around 940,000 people (an extra 7.5%) between 2005 and 2015. That means Tokyo, like many big cities around the world, has the challenge of how to ensure there’s enough housing to go around. But unlike most big cities around the world, Tokyo is actually meeting that challenge.

Annual housebuilding statistics in Tokyo are expressed in terms of dwelling starts rather than completions. The chart below (compiled from various years of the Tokyo Statistical Yearbook) shows the trend in new dwelling starts in Tokyo between 1995 and 2015. Starts hit a peak of 192,000 in 2003 and a trough of 108,000 in 2009 but averaged 155,000 new homes over the two decades.

But that’s new supply in gross terms and everyone knows the Japanese demolish housing at a much higher rate than most countries, so what’s the net growth like? The chart below (from table 5 here) shows how the number of homes in Tokyo changed between 1963 and 2013 (based on the five-yearly Housing and Land Survey, the latest one of which was carried out in 2013). In just a fifty year period Tokyo’s housing stock nearly tripled in size, from 2.51 million homes in 1963 to 7.36 million in 2013.

Tokyo does demolish a lot of housing – between 2002 and 2011 there were 1.58 million starts but between 2003 and 2013 the stock grew by 1.17 million, so if we assume that it takes an average of two years from start to completion then it looks like 0.41 million homes were demolished in a decade, or about 7% of the 2003 stock. Put another way, roughly one home is demolished for every four new ones built. But the scale of construction still means that Tokyo’s housing stock is growing very fast – roughly 2% a year, about twice as fast as that of Paris, London or New York as the chart below (from the GLA’s Housing in London 2017 report) shows.

In 1963 there were 2.69 million households in Tokyo, and by 2013 this had grown to 6.51 million. So while the number of households grew quickly, the number of homes grew faster, and Tokyo went from having a crude ‘housing deficit’ in 1963 to a ‘surplus’ in 1973, and an even bigger surplus every year after that. By 2013 there were 849,000 more homes than households.



What strikes me about this chart is that at every point after 1968 Tokyo had (a) more than enough housing to go around (by this measure, anyway) and (b) more than it had ever had before. It is often said that by those criteria the UK should stop focusing on new trying to increase new supply and should instead focus on a better distribution of its existing housing. But Tokyo illustrates another strategy: keep building more and more housing, far past the point of mere sufficiency and into the realm of abundance.

The next chart shows the change in the type of dwellings in Tokyo between 1978 (the furthest back the data goes) and 2013. The fastest growth has been in apartments, particularly the tallest ones (six storeys or more). In 1978 there were 823,000 homes in Tokyo in apartment buildings of 3 or more storeys. 25 years later there were 3.6 million. Over the same period the number of houses grew slightly while the number of low-rise apartments fell. All of this is consistent with a pattern of housing growth achieved primarily through densification rather than sprawl.

That’s backed up by data on land use, which indicates that the acreage devoted to housing in Tokyo grew by around 1.5% between 2006 and 2011, whereas the number of homes grew by 9.2%. On average there are around 110 dwellings per hectare of residential land in Tokyo, compared to roughly 60 in London as of 2005 (the last time similar land use statistics were collected).

Really fast densification in an already built-up area like Tokyo can only be achieved through demolition and redevelopment, and we’ve already seen that around one existing home is demolished for every four new ones. The next chart shows how that trend has affected the age of profile of Tokyo’s housing stock over time. For obvious reasons there aren’t many dwellings in Tokyo dating from earlier than 1950, but even the stock of homes built in the 1950s and 1960s is dwindling fast: in 1998 there were 856,000 homes originally built between 1951 and 1970, but only 15 years later in 2013 this had fallen to 451,000. Replacing swathes of old housing with taller, denser new housing is what enables Tokyo to grow its housing stock so fast.

What does all this new construction mean for the amount of housing space available? Tokyo has a reputation for tiny apartments, and at 64m2 its average dwelling size is indeed smaller than what most Westerners would be used to, although it has risen over time.

The average size of new homes in Tokyo is very similar, at 65m2 (down from around 80m2 in the late 1990s).

But what these figures on average dwelling size don’t tell you is that the average Tokyo resident has far more space today than they did fifty years ago. The reason is that the average number of people in a Tokyo household has plummeted over this period, from 3.6 in 1963 to 2.0 in 2013. Of course, this could only happen because there was so much housing available for people to move into. When there isn’t enough housing then you get the opposite effect – of multiple unrelated people living together, and rising household sizes. London’s a good example of this.

When you combine the average floorspace per home and the average number of people per household you get the below trend in average floorspace per person (this shows the space in occupied homes only – if you took vacant homes into account it would be much higher). The amount of space per person saw a remarkable increase from 15m2 in 1963 to 32m2 in 2013. Londoners have a similar amount of space per person on average today (assuming similar methodologies for measuring floorspace – there’s not enough detail in the Tokyo stats to tell), but in stark contrast to Tokyo there has been little or no increase in London in around 20 years (according to this article, which in classic UK-housing-discourse style seems to suggest that it’s evidence against a housing shortage).

So how come Tokyo is so good at building housing? That’s a long story in itself, but this Robin Harding article in the FT is a good place to start, and if you want to dig into the academic literature try here, here and here. In short, Japan has a relatively simple and unambiguous zoning code, one which the national government has repeatedly adjusted in order to allow for more housing growth in Tokyo. That has been done in the face of opposition at neighbourhood and even city level, opposition that in countries which have devolved land use decisions to a local level would be enough to stop densification or at least divert it to poorer areas. What you might call the ‘supersidiarity’ of Japan’s approach to housing policy is therefore quite progressive, as well as being extremely effective in getting housing built.