The road access requirement and non-rebuildable land ― what "2 metres onto a road" means, and what you can do with land that cannot be rebuilt on

To build, a site must adjoin a road at least 4 metres wide along at least 2 metres. Why does "non-rebuildable" (再建築不可) land that fails this road access requirement (接道義務) arise, what can be done with it, and how can the problem be resolved? This article covers the types of road under the Building Standards Act, setbacks and permission under Article 43, from the practical viewpoint of a licensed real estate agent.

About this translation ― This page is an English translation of an article originally written in Japanese by KuraLab's operator, a licensed real-estate transaction specialist (宅地建物取引士) and administrative scrivener (行政書士) in Japan. The Japanese original is the authoritative text; where the two differ, the Japanese version prevails. The article explains Japanese law and procedure in general terms as of the date shown. It is not legal, tax or immigration advice for your situation ― please confirm with a licensed professional in Japan. Japanese terms are kept in parentheses so you can search for them. Read the Japanese original

At the very bottom of the valuation, in small print, it said "non-rebuildable" (再建築不可). It was the second of three valuations a woman had requested for the family home she had inherited. The first company said 21,000,000 yen, the second 9,000,000 yen, the third "we cannot handle this." The same house. The first company had not looked at the road. The second had. The third had looked and given up. This article is about the reason for the 9,000,000 yen, and the eight months it took for 9,000,000 yen to become 19,000,000 yen.

"This land is non-rebuildable." When this phrase comes up in the investigation of a second-hand house or inherited land, the price changes by an order of magnitude. At the root is the "road access requirement" (接道義務) in Article 43 of the Building Standards Act (建築基準法). A site on which a building is to be built must, in principle, adjoin a road at least 4 metres wide along at least 2 metres. On a site that does not meet this, no building confirmation will be issued for a new building after the existing one is demolished. That is non-rebuildable land.

What matters here is that the "road" must be a road under the Building Standards Act. There are passages and private roads that look like roads but are not recognised as roads in law. Article 42 of the Act defines roads as follows: roads under the Road Act (national, prefectural, municipal roads and so on), roads under the City Planning Act or the Land Readjustment Act, ways at least 4 metres wide that already existed when the Act came into force (November 1950), and designated-position roads (位置指定道路) designated by the specified administrative agency. These are roads under Article 42, paragraph 1.

There is one more: roads under Article 42, paragraph 2 (deemed roads, みなし道路). These are ways less than 4 metres wide along which buildings already stood when the Act came into force, designated by the specified administrative agency. A site adjoining such a road can be built on, but with a condition. A line 2 metres back from the centre line of the road is deemed to be the road boundary, and at a rebuild the site must be set back to that line. This is the "setback" (セットバック). The part set back cannot be counted as site area, so the size of the building that can be built shrinks.

The main types of road under the Building Standards Act are: Article 42(1)(i), roads under the Road Act (national, prefectural, municipal), which meet the road condition if 4 metres or wider; Article 42(1)(ii), roads created under the City Planning Act, Land Readjustment Act and the like (development roads), the same; Article 42(1)(iii), ways 4 metres or wider that existed when the Act came into force in 1950, the same; Article 42(1)(v), designated-position roads (private roads designated by the specified administrative agency), where you check the designation in the road register; Article 42(2), ways under 4 metres lined with buildings at the time of enforcement (deemed roads), needing a 2 metre setback from the centre line; and none of the above, undesignated private roads and passages, which do not satisfy the road access requirement and are in principle non-rebuildable.

There are three typical ways land becomes non-rebuildable. One: the way it adjoins is not a road under the Building Standards Act (a mere passage, an unrecognised private road). Two: it adjoins a road, but along less than 2 metres (the stem of a flag lot is narrow). Three: the width is insufficient for the length of the stem (some municipal ordinances require a wider stem the longer it is). As noted in another article on this site about flag lots, the third differs by municipality, so check with the building guidance section of the municipal office.

So what can be done with non-rebuildable land? You can continue to use the existing building. Repairs and renovations that do not need building confirmation (updating interiors and equipment that do not affect the structure, and so on) are also possible. But extensions and large-scale alterations that require building confirmation are not. If you demolish a dilapidated building, what remains is land on which nothing can be built. When selling, buyers find it hard to get a home loan, so the market tends to be limited to cash buyers or the neighbouring owner.

There are ways to resolve it. First, acquire or lease part of the neighbouring land to bring the road frontage to 2 metres or more. Second, work with the owners of the private road to have it designated as a designated-position road. Third, permission under Article 43, paragraph 2 of the Building Standards Act (the so-called proviso permission). This is a system under which the specified administrative agency permits building even without road access when it finds no safety problem, for example where there is wide open space around the site or it adjoins a farm road or a park. It is an individual review requiring the consent of the building review board and takes time, but there are plenty of cases in practice where this made rebuilding possible.

The order of investigating land is fixed. First confirm the shape of the land and the adjoining parcels on the cadastral map and the register. Next, in the municipal road register, confirm whether the adjoining way is a road under the Building Standards Act, which paragraph and item of Article 42, and its width. Then measure the width and length of the stem on site. Completing these three before talking about price is the basic discipline of a licensed agent.

In the order we checked. On the cadastral map, the north side of the site adjoined a way about 3 metres wide; the way was a private road used by six houses up to the dead end. In the municipal road register, this private road was not designated as a road under the Building Standards Act. Not a paragraph 1 road, and no paragraph 2 designation. A mere passage. The site adjoined only this passage, so it failed the road access requirement and was non-rebuildable. The first company's 21,000,000 yen was a number produced without this check.

We considered three ways to resolve it. First, buy part of the neighbouring land to reach the public road. The house to the east faced the public road, and if a 2 metre strip at the edge of its site could be bought, the site would adjoin the public road along 2 metres. We approached the neighbour: "not selling." Second, permission under Article 43, paragraph 2 (the proviso permission). The passage was 3 metres wide, used by six houses, with a municipal park at the dead end. A preliminary consultation with the municipality gave the impression that "given the width of the passage and the connection to the park, it is worth putting to the building review board." Third, designation as a designated-position road. This needed the consent of all six private road owners and widening to 4 metres, and was not realistic.

We chose the second. We engaged an architectural office to prepare a plan assuming a rebuild, a survey of the current state of the passage and an explanation of evacuation routes, and applied for permission under Article 43, paragraph 2. Five months to the building review board's consent, eight months to the permission. The cost, for the architectural office and the application, was about 650,000 yen. Once the permission was granted, the land became "land that can be rebuilt on with permission," and when we asked the second company to revalue it, 19,000,000 yen. The buyer purchased for 18,500,000 yen, taking over the permission documents. The difference between 9,000,000 and 18,500,000 yen, 9,500,000 yen, was the return on eight months and 650,000 yen.

The reason the Land Price Scan tool (土地価格スキャン) on this site lets you choose road access conditions is that "whether it adjoins a road, and along how many metres" bears directly on the price. Enter the shape of the land you traced and its road access, and an adjustment is applied to the reference price based on official land prices.

The three valuations were 21,000,000 yen, 9,000,000 yen and "we cannot handle this." The correct one was 9,000,000 yen, and the one that could be changed was also 9,000,000 yen. Of the order I described, "first the cadastral map and register, then the road register, then the site," the first company skipped it and the third stopped partway. "Non-rebuildable" is a phrase that changes the order of magnitude of a land price, but beyond that phrase there are still three roads.

Written by: 長澤湊（licensed real-estate transaction specialist, administrative scrivener, assistant surveyor）　Content checked on: 2026-10-14

This article is a general explanation of Japanese rules and procedures, not advice on an individual case. Figures and rules are as of the date shown. For your own situation, consult a lawyer, judicial scrivener, tax accountant or administrative scrivener in Japan.

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