1. The key dates
| Approval date | Standard | What it means |
|---|---|---|
| Before 1 June 1981 | Old standard (旧耐震) | Designed for moderate quakes; highest risk group |
| 1 June 1981 – May 2000 | New standard (新耐震) | Designed not to collapse in a major quake |
| June 2000 onwards | 2000 standard | Stricter joints, wall balance and foundations for wooden houses |
The date that counts is when the building plans were approved (建築確認), not when the house was finished.
2. What it means for buyers
- Safety: old-standard wooden houses performed worst in past major earthquakes.
- Loans: some lenders shorten terms or decline older houses.
- Tax breaks: some reliefs need proof the house meets the new standard.
- Insurance: earthquake insurance discounts usually require newer standards or a certificate.
- Price: many cheap akiya are pre-1981, which is part of why they are cheap.
3. What to do before you buy
- Confirm the plan approval date from the disclosure documents or the city.
- Book a seismic assessment (耐震診断) — ask the city whether it subsidises one.
- Get a quote for strengthening if needed; for small wooden houses it is often ¥1–3 million, but it varies a lot.
- Ask about strengthening grants, and apply before any work starts.
See the renovation subsidies guide and try the renovation cost estimator, which includes a strengthening option.
Frequently asked questions
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