What do you mean my property shrank?!: Checking roads when purchasing property

In the world of real estate, roads are the seams that bind all properties together in a complex web that weaves its way through the country. Japan, with its sometimes surprisingly narrow roads is no different. Although they do not officially “belong” to the property in most cases, the streets are an essential aspect to consider before purchasing real estate. Not paying attention to the roads before purchase could even mean that your property size could be reduced in the future. Therefore, we are going to take a look in this article about the implications roads can have on property purchase.

Width of the Road

According to the Building Standards Act, the official regulation is that roads must be at least 4 meters (2 meters on each side of the center) wide. This law is to ensure that rescue vehicles can reach the property in case of an emergency.

This law is applicable for the vast majority of roads in Japan, but there are certain classes of roads that are required to be larger to accommodate larger buildings or other special circumstances. Therefore, it is important to find out the specific building standards for the lot you plan to purchase.

Of course, as with many rules, there are exceptions. Depending on the location of the property, the road may need to be more than 4 meters wide. In regions with heavy snowfall, for example, 4 meters is not nearly wide enough and could even require a width of 6 meters!

The appropriate width of the street as well as whether or not the property has already been adjusted can be checked at the local authority responsible for building permits. Confirming this information can be quite a hassle for anyone who does not live in the region in where the property is located. Although in metropolitan centers such as Tokyo or Osaka this information can sometimes be obtained online, physical visits to local authorities may also be necessary.


Unfortunately, the Building Standards Act did not come into effect until 23 November 1950. This means the roads built before this date may not comply with the standard. In these cases, the law is enacted retroactively. This doesn't mean that buildings are not demolished solely for the purpose of expanding the road. Should a building be demolished for other reasons, the road is also expanded to meet the 4-meter standard. 

Each side must be 2 meters away from the center of the original road. This means that the same amount of space is added to both sides equally. The process of expanding the road is called "setting back," since new buildings need to be built farther from the center of the road. In these cases, parts of the land on both sides of the road are, in most cases, "returned" to the government to expand the width of the road. The floor area ratio, then is recalculated based on the new area of the lot.

Of course in some cases natural features such as rives, cliffs, etc. mean that this is not possible. In these cases, roads are expanded on one side only, so a larger percentage of the property is used.

Connection to a Road

By law it is required that all properties with buildings be connected to at least one “legal” road (at least 4 meters wide). But what is meant by “connected”? According to the Japanese government, the lot must have at least 2 meters touching a legal road. 

Due to historical boundaries, natural phenomena, and changes over the years, some properties have acquired irregular shapes. Yet, even in these situations, it is still required that the properties have at least 2 meters touching a legal road. Although in some cases, properties are completely surrounded in a block, they will have a narrow “handle” that connects to the street. These are called “flagpole” properties due to their shape. Although one may expect them to fulfill this rule, it is always better to double check with the local authorities.

An exception can be made to the 2-meter rule if you are purchasing a plot of land surrounded by large empty lots. To qualify for this exception, the building review council must perform an inspection and grant approval.


In most cases newly built properties adhere to all of the standards set forth in the Building Standards Act, but buyers interested in second-hand real estate should pay special attention to these portions of the Explanation of Important Matters. Since this information is available from various government organizations before the time of sale, it is a good idea to confirm all of the information well in advance.

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