Old Earthquake Rules and Akiya Condition: What the 1981 Standard Means and Who Checks a House

Many akiya are old. That is part of the appeal, and part of the question. The date a house was built tells you which earthquake rules applied when it was designed. It does not tell you what condition it is in today. This guide explains what the 1981 standard is, what a year built can and cannot tell you, and who actually checks a house.

We are a directory, not a surveyor, and nothing here is structural advice. Where a point needs an expert, we say who.

What is the 1981 standard?

Japan changed its building rules for earthquakes in June 1981. The newer rules are often called the "new seismic standard" (shin-taishin). Buildings designed to the older rules were built to a weaker requirement for strong shaking. The change applies to building permits from 1 June 1981.

Our wider safety guide sets this alongside flood, landslide and tsunami risk. For the rules themselves, go to the official source: the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) publishes the building standards.

How many akiya on Engawa were built before 1981?

Most of the homes where we know the year. As of 8 October 2026, of the homes with a known build year, about 7 in 10 (4,621 of 6,761) were built before the 1981 standard. Here "before 1981" means built in 1980 or earlier.

• 8,668 live homes in total.
• 4,621 built in 1980 or earlier.
• 1,771 built between 1981 and 2000.
• 369 built after 2000.
• 1,907 with no year built listed.

The 152 homes listed as built in 1981 are the grey area, and they are counted in the 1981 to 2000 group. If you count every 1981 home as old standard too, the figure is 4,773 of 6,761, or 70.6%.

For five larger prefectures, the counts look like this, as of 8 October 2026:

Homes with no year built are a real gap. In Shimane, 112 of 303 homes have no year listed. In Fukushima, 220 of 363 do not. Where a year is missing, we show nothing rather than guess.

What does a year built tell you?

• Which rules applied. A house built in 1975 was designed to the older standard. A house built in 1995 was designed to the newer one.
• Roughly how old the materials and methods are. That helps you think about what questions to ask.
• Where to start. A house from 1980 or earlier is a reason to ask for an inspection, not a reason to walk away.

What does a year built not tell you?

• Whether the house meets the 1981 standard. The listing gives a year, not a permit date, so a home listed as 1981 could fall on either side. We cannot tell from the data.
• Its condition today. Rot, damp, termites, past repairs, a sagging roof or an extension added later can matter more than the original year.
• Whether it has been strengthened. An older house may have been reinforced. A listing may not say.
• What the structure is made of. Most listings give a structure, such as wood, but many do not, and the detail varies.

An older house is not automatically unsafe, and a newer one is not automatically sound. The year is a clue. A person looking at the building gives you the answer.

Who checks the condition of a house?

Not Engawa, and not a listing. In Japan, the people who can look at a house include:

• A licensed building inspector or architect, who can survey the house in person. A listed agent or your own adviser may be able to point you to one in the area.
• A structural engineer or architect for a seismic assessment. Some municipal subsidies fund earthquake work, so see akiya renovation subsidies explained and ask the municipal office for the area. The national ministry (MLIT) publishes official building and housing information at https://www.mlit.go.jp/en/.
• The municipal building or planning office, for the official rules that apply to a particular plot.
• Your insurer, who will have its own questions about age and structure.

Commission any survey before you commit. We do not visit sites or grade condition, and we cannot judge the structure from photographs.

A simple inspection checklist to take to the survey

This is a list of questions, not advice on what the answers mean.

• Year built, and any record of permits or later work.
• Whether any seismic assessment has been done, and what it covered.
• Foundation, roof, walls, floors and any signs of damp.
• Structure type: wood, steel or reinforced concrete.
• Any extensions or outbuildings, and whether they are registered.
• Who pays for repairs found, and how you would budget for them: see what akiya renovation really costs.
• The site hazards: how to read a Japanese hazard map.

A note on our other figures

You may see older numbers on Engawa, from earlier, much smaller catalogues. The figures on this page are from 8 October 2026 and cover 8,668 live homes. Where two numbers differ, trust the one with the newer date.

Frequently asked questions

Is a house built before 1981 safe to buy?

We cannot say. It means the older rules applied when it was designed. Whether the house is sound is a question for a qualified surveyor or architect who has looked at it.

What if the listing says 1981?

Treat it as uncertain. The rules apply by permit date, from 1 June 1981, and a listing shows only a year. Ask the agent or the seller for the permit information.

Where can I find the official rules?

MLIT, the national ministry, publishes the building standards. For a specific house, ask the municipal office for the area.

Does Engawa inspect houses?

No. We show the year built and the hazard layers from official sources, with links. A physical survey is a separate step.

Next step

Find a home in Explore and check its year built and hazard layers. If you have questions about a specific house, use "Enquire about this house". In the prefectures a listed agent covers, your message reaches the agent and us together. Elsewhere, one of the founders replies and can put you in touch with a licensed agent.