How To Check If A Japanese Property Meets Earthquake Standards

The dividing line is June 1, 1981 — but it's the confirmation date, not the completion date

Japan's Building Standards Act (建築基準法) seismic design requirements were substantially revised effective June 1, 1981, following lessons from the 1978 Miyagi earthquake. A building whose 建築確認 (kenchiku kakunin, "building confirmation," the pre-construction permit) was approved before that date falls under 旧耐震基準 (kyu-taishin kijun, the "old standard"); one confirmed on or after that date falls under 新耐震基準, the new standard.

The common mistake is checking a building's completion or move-in date instead. Confirmation happens before construction starts, so a house finished in late 1981 or even 1982 can still have been confirmed — and therefore designed — under the old standard if the application was filed and approved before June 1, 1981. The completion date alone does not settle the question.

What actually changed, and why 1981 isn't the only date that matters

The old standard was designed around a building surviving a seismic intensity of upper-5 (on Japan's shindo scale) without collapsing. The 1981 revision raised the bar considerably: a building should not be seriously damaged in an upper-5 event, and should not collapse even in the rarer upper-6 to 7 range. The 1995 Great Hanshin (Kobe) earthquake gave a stark real-world comparison — wooden buildings built to the old standard suffered major structural damage or worse at a far higher rate than those built to the new one, according to MLIT's post-earthquake damage survey by construction year.

That same 1995 earthquake also exposed weaknesses in some post-1981 wood-frame buildings, particularly around wall-brace balance and how joints were fastened. A further revision, generally called the "2000 standard" (2000年基準), took effect in June 2000 and required, for wood-frame houses specifically, that foundations be designed according to the ground's actual bearing capacity — which in practice makes a ground survey standard before building, though it is not a categorical mandate for a specific survey document in every case — plus specified connector hardware at structural joints and a balanced layout of load-bearing walls. So for an older wood-frame house, "built after 1981" and "built to today's expectations" are not quite the same claim — a house confirmed between 1981 and 2000 already meets the new standard, but may still predate the 2000-standard detailing that mattered most in Kobe.

Here is a practical way to check before you get attached to a listing:

1. Start with the registration record's recorded construction date. A building's registration record (登記事項証明書) lists a construction date in its descriptive section, under 原因及びその日付 ("cause and its date"). This is a useful first screen — order the building record through How To Order A Japan Property Registration Record In English — but treat it as an approximation, not proof: it typically reflects the completion or registration date entered by the land and house surveyor (土地家屋調査士), not the 建築確認 date, and it can be blank or approximate on some older or rural buildings.
2. If the recorded date is anywhere near 1981–1982, don't guess — get the confirmation date itself. Ask the seller or listing agent for the original 建築確認済証 (confirmation certificate) and 検査済証 (completion inspection certificate). Many older properties, especially akiya, no longer have these on hand.
3. If the certificates are missing, request a certified copy from the municipal building department. The building permit authority (建築主事) covering the property's location can issue a 建築確認台帳記載事項証明書 (a certified extract of the confirmation ledger) confirming the actual confirmation date, and can let you view the 建築計画概要書 (building plan overview) on file. Procedures and required documents vary by municipality, so check with the specific building department (建築指導課) for the property's city or ward.
4. For a wood-frame house near the 2000 boundary, ask what the confirmation date actually was, not just whether it's "new standard." A 1985-confirmed wood house is 新耐震 but predates the 2000-standard detailing — worth knowing before assuming it matches current expectations.
5. If the property predates June 1981 (or the date can't be confirmed), budget for a proper seismic diagnosis before relying on the building as-is. A 耐震診断 (seismic diagnosis) by a licensed architect is what actually tells you the building's current structural adequacy, regardless of which standard it was designed under.
6. Loop in a judicial scrivener (司法書士) or licensed architect once the date is unclear or the standard is old. Confirming a confirmation date through municipal records, or judging whether a diagnosis and retrofit make sense for a specific property, are worth professional input rather than guesswork.

The most common mistake is treating "built after 1981" as settled by the registration record's construction date alone, when that date is normally the completion date and can differ from the confirmation date that actually decides the standard.

What the registration record can and cannot tell you here:

• What it shows: a recorded construction date for the building, in the descriptive section of the building's registration record (登記事項証明書) — useful as a first-pass screen for how old a building is.
• What it does not show: the 建築確認 date that actually determines old vs. new standard, whether the building has since had a seismic retrofit, or the results of any structural diagnosis. None of that is registry data.
• How to order the record: Order the building registration record for ¥1,500 to see the recorded construction date. For a house, this is separate from the land record, since land and buildings are registered independently in Japan.

Beyond the registry, the standard also affects financing and certain tax treatments. Many Japanese lenders are more cautious about financing a pre-1981 property without retrofitting, and several tax programs — the mortgage interest deduction, the real estate acquisition tax reduction, and the registration tax reduction among them — commonly use a related but not identical proxy: a house completed on or after January 1, 1982 is treated as meeting the new standard automatically, while an older one generally needs a 耐震基準適合証明書 (a seismic standard compliance certificate, issued by a qualified architect or a designated evaluation body after a seismic diagnosis) to qualify. These rules and thresholds are adjusted from time to time, so confirm the current requirements with a tax accountant or the judicial scrivener handling your purchase rather than relying on a general guide for the exact figures. Our Japan property due diligence checklist covers where this check fits alongside ownership, mortgages, and boundaries.

FAQ

What does 新耐震基準 mean? It refers to Japan's earthquake-resistant building standard that took effect June 1, 1981. A building is judged "new standard" or "old standard" (旧耐震基準) based on when its building confirmation (建築確認) was approved, not when it was completed or when you view the listing.

Is a pre-1981 house automatically unsafe? No, not automatically — but it was designed to a lower structural target, and its actual current condition depends on maintenance and whether it has been retrofitted. A seismic diagnosis (耐震診断) by a licensed architect is the only way to know its present-day adequacy, not the standard it was originally built to.

Does the registration record tell me which standard a building meets? Only approximately. It records a construction date, which is normally the completion date used by the surveyor who filed the registration — not the 建築確認 date that actually decides old vs. new standard. Treat it as a first screen, not final proof.

How do I get the exact confirmation date? Ask the seller or agent for the original 建築確認済証 and 検査済証. If those aren't available, the municipal building department (建築指導課) covering the property can issue a 建築確認台帳記載事項証明書 confirming the date, or let you view the 建築計画概要書 on file.

Does this matter for financing and taxes? Yes. Many lenders are more cautious about financing an older, unretrofitted property, and several tax programs use a related January 1, 1982 completion-date proxy, requiring a 耐震基準適合証明書 for older houses. Confirm current thresholds with a tax accountant or judicial scrivener, since these rules change.

Is "built after 1981" the same as "meets today's expectations"? Not quite for wood-frame houses. A further revision — the "2000 standard" — added stricter connector and wall-balance rules for wood construction after lessons from the 1995 Kobe earthquake, where some post-1981 wood houses still performed poorly. A house confirmed between 1981 and 2000 meets the new standard but predates that additional detailing.

Related guides:

• What Is Touki In Japan
• Akiya Guide For Foreign Buyers In Japan
• How To Check If A Japanese Property Has An Unregistered Building
• How To Order A Japan Property Registration Record In English
• Japan Property Due Diligence Checklist

• 阪神・淡路大震災 建築年別の被害状況（建築物） — Ministry of Land, Infrastructure, Transport and Tourism (MLIT) — official damage survey breaking down building damage by construction year and standard (大破以上 = "major damage or worse")
• Earthquake Building Codes and Technology in Japan — Real Estate Japan — overview of the 1981 Building Standards Act revision and design targets
• Differences Between Pre- and Post-1981 Earthquake-Resistant Standards in Japan — Dovetail — confirms the confirmation-date (not completion-date) rule and lender caution on pre-1981 properties
• 新耐震と旧耐震の違いは？見分け方と基準はいつからか解説 — Zaiju Business — confirms the June 1, 1981 building-confirmation cutoff and old/new design targets
• 1981年（昭和56年）の耐震基準とは？旧耐震・新耐震の違いと確認方法を解説 — Fundex — practical guidance on checking a building's confirmation date via municipal records
• 「旧耐震基準」「新耐震基準」「2000年基準」…あなたの家はどの基準？ — Suzuki Jyuuken — background on the June 2000 wood-frame structural revision following the 1995 Great Hanshin (Kobe) earthquake
• 地盤調査と建築基準法について — Building Standards Act Enforcement Order Arts. 38 and 93 require foundations to safely bear the building's load and ground-bearing capacity to be determined by survey, which in practice makes a ground survey standard rather than directly mandating one in every case
• 耐震基準適合証明書とは？取得するメリットや費用とあわせて注意点も解説 — Tokyu Livable — how the seismic standard compliance certificate is obtained and who can issue it
• インターネットでの建築確認申請台帳記載証明書の取得方法について — City of Yokohama — example municipal procedure for obtaining a certified extract of the building confirmation ledger