
Tokyo has origins of inhabitation dating back to 3000 BC. In fact, the Yoyogi-Hachiman Shrine just west of Yoyogi Park in Shibuya has traces of a historic settlement from the middle Jomon period (2500~1500 BC).
By 1800, this was the largest city in the world with a population of over 1 million. The city’s growth and frequent rebuilding over the years, especially during the 20th century, helps to explain why Tokyo is the way it is and how it differs from other international metropolises.
In the early 1700s, during the Edo period (1603 – 1868), Edo (now Tokyo) had a total area of 69.93 square kilometres, just 11% of the current size of Tokyo’s 23 wards. Of that, 67% of the land was occupied by samurai clans, 12% by merchants, and 15% by temples. At the time there were 450,000 samurai and 550,000 merchants. The density for the samurai-occupied land was approximately 103 sqm (1,108 sq.ft) per person, while merchants were stuck with just 16 sqm (172 sq.ft) per person. In 2016, there was approximately 67.70 sqm (728 sq.ft) per person based on the city’s resident population.
The feudal system at the time meant that all land was owned by the Tokugawa shogunate and leased to feudal lords. It wasn’t until the land reforms during the Meiji Restoration in the late 1800s (when all shogunate land was returned to the Emperor) that land could be owned by individuals. From 1873 onwards, individuals could finally own freehold land. Daimyos and shogunate administrators inherited some of the land that they had previously been occupying from the shogunate. Some of the grand properties once owned by the Daimyo class were later converted into foreign Embassies, and the surrounding neighbourhoods have continued to retain high property values to this day.

One year after the devastating 1923 Kanto earthquake that saw much of Tokyo reduced to rubble and ashes, the Dojunkai corporation was established to provide desperately needed disaster-proof housing. Between 1925 and 1934, 16 Dojunkai apartment buildings were built across Tokyo and Yokohama and several housing subdivisions were also developed. Although cheaper row-houses and tenements already existed throughout the capital, these were owned by landlords and prone to frequent fires. Unfortunately, the Dojunkai apartments have been demolished in recent years to make way for redevelopment, although there are still some traces of the original housing subdivisions.
According to a survey on housing stock in 1941, detached houses comprised 48.6% of all residences in Tokyo’s wards, while tenements or row-houses accounted for 43.3% of stock. Multi-unit dwellings (such as flats or apartments) accounted for just 8.1%.
In 1945, the city was destroyed once more. This time by WWII air raids. Approximately 159 square kilometers of central Tokyo were completely scorched. Over 1 million residents were forced to evacuate to surrounding areas, building makeshift temporary housing on small parcels of land. After the war, these temporary dwellings were often re-built as small wooden houses.
During the post-war occupation, the GHQ (General Headquarters) introduced a one-time asset tax on the wealthy. Landlords owning large tracts of land were hit hard, with tax rates as high as 90%. Faced with extraordinarily high tax bills, former nobles and peers were forced to sell off their large estates, resulting in smaller and smaller subdivided blocks of land.
In 1963, during Japan’s ‘Golden Sixties’ and just after the post-war period of rapid economic growth, detached houses accounted for 48.9%, row-houses accounted for 10.7% and multi-unit dwellings accounted for 32.8% of housing stock. In 2008, detached houses accounted for 23.1%, row houses accounted for 1.7%, and the share of multi-unit dwellings reached 73.7%.
The change in housing in Tokyo:

In the 1970s, during the era of Japan’s second baby boom, there was a rapid expansion of banks offering home loans to ordinary citizens. This led to a steep increase in demand for housing. Developers were quick to capitalize on the new demand and subdivided land in to small blocks fronting very small streets, some no bigger than a pathway. The developers would skirt around building laws by applying for building permits for row housing only to change the final buildings into detached houses.
In Nakano ward, for example, 1,860 houses currently have no street access and 12,090 houses have street frontage of less than 2 meters. 64,340 houses (over a third of all houses in the ward) front onto roads between 2 ~ 4 meters wide.
In 1975, the average house block in Tokyo was approximately 433 sqm (4,659 sq.ft). But by 2013 it had shrunk to 180 sqm. Approximately half of the privately-owned housing blocks are less than 100 sqm in size, and many of those are in the 60 ~ 90 sqm range.
Subdividing land into smaller and smaller lots has the unexpected effect of decreasing the general land prices in the surrounding area. An increase in houses and the disappearance of large trees and gardens have a negative effect on the streetscape and appeal of a neighbourhood. A survey by the MLIT in 2008 found that if the 3 lots surrounding a block were subdivided into small plots, the value of the land at the center would drop by about 4.3%. If this happens on a larger scale in the general neighbourhood, land can fall in value by 25.1% in a worst-case scenario.

Sources:
Home’s Press, June 6, 2016.
Home’s Press, April 20, 2016.