Was postwar Tokyo a slum? This question has been at the heart of several posts on this blog. The first detailed Housing Survey allowing for a ward-level analysis in 1963 can help answer this question to some extent.

Among the information I extracted were figures on living space per capita as well as sanitary conditions in Tokyo’s dwellings. I found out that “space poverty” was a shared phenomenon across the ward area and that sanitary conditions were geographically unequal but improving.

The first map above (created with a basic GIS software, an approach I dropped for the final thesis) shows the proportion of dwellings in which each resident has less than 3 tatami (5 square meters) mats of living space.

This roughly equals the percentage of the population living in such conditions. However, there are dwellings with more than one household, and household size varies across the wards, which is why the figures would differ slightly. 32.0% of all dwellings of the entire ward area fall into this category of small dwellings.

The largest proportion of these is found in Adachi (45.6%), followed by Arakawa (43.8%) and Koto (42.9%). The smallest proportion is in Chiyoda (7.9%), Minato (19.0%) and Suginami (21.8%).

Overall, the map shows that there is a slight concentration of these dwellings in the east. However, Ota and Itabashi, too, have a high proportion of these small dwellings, suggesting that this is a much more widespread phenomenon and affects a large part of the rental population regardless of where they are living in Tokyo.

The calculation of these values is not entirely straightforward. Usually, at a city-wide level the 2.5 tatami mat per person (approximately 4 sqm) was being used to define extremely dense living conditions. In 1960, the proportion of people in the whole of Tokyo living on less than that was 39.8% (national census data). Although average living space per person is available per ward, the proportion living under 2.5 tatami is not.

The housing survey, however, runs slightly complex tables that show how many people live in dwellings of a certain size. From these we can add up the number of dwellings of a certain size (e.g. 6-9 tatami mats) which were inhabited by a certain amount of people or more that would bring the per resident allocation of living space below 3 tatami mats (the lowest available unit, and common denominator). The following table illustrates the calculation that was performed.

Table: Calculation method for determining small dwellings

On a consolidated ward level, the 1963 housing survey does show that 17.6% of all households live in “density I” (p. 92), a category that is defined as offering its inhabitants less than 2.5 tatami mats each. However, the addition of tatami mats per household member stops with household size of four (for which 9 tatami mats or less are considered “dense”).

Does this information help answer the question whether Tokyo was a slum? According to UN Habitat, a dwelling is considered “slum-like” if there are less than three people sharing a room and if it is bigger than four square meters.

From that standpoint, 2.5 tatami per person far exceeds that limit. However, the extent of relative space poverty is perhaps surprising. And yet this analysis would stand on stronger feet if compared to other cities at this point in time.

One thing I did in the thesis is to also perform this analysis for 1968. What I found was that the proportion of people living on less than 4 tatami mats became smaller during these five years.

More importantly, the variability of this proportion between the wards became smaller. In other words, wards with comparatively small living space caught up with wards with comparatively large living space – a positive development for a city growing as fast as Tokyo.

The map above shows how the different wards score on an easily constructed “sanitary index”. The index adds up the proportion of dwellings with their own water supply (max 100% = 1.0), their own sink, own toilet, flush toilet and own bath (altogether max 500% = 5.0).

We see that dwellings in the central wards have relatively good sanitary conditions (e.g. Chiyoda, 4.34), followed by three western wards of Setagaya (3.41), Suginami (3.29) and Nerima (3.26).

Their good scores may also be explained by the physical proximity to Tokyo’s water supplies and their correspondingly good connectivity to the sewage system. Apart from this, the wards surrounding the center in the east, north and south, as of 1963, have comparatively poor sanitary conditions.

Some examples can illustrate this: Only 58.5% of dwellings had their own toilet in Toshima, only 25.1% their own bath. Only 4.6% of all dwellings in Edogawa had flush toilets. This compared to 93.8% of all dwellings having their own (flush) toilet in Chiyoda. While only 70.9% of all dwellings had exclusive access to a toilet, 99.0% of these were flush toilets in Taito.

The following graph exemplifies how few households in the ward area were fully connected to the water system including freshwater and sewage. A material improvement in the situation occurred only after 1965, with much more investment on a per capita in Tokyo’s sanitary systems.