Japan Old vs New Seismic Standards: The 1981 Rule and Checks for Existing Property
For existing Japanese property, the distinction between the pre-1981 “old” seismic standard and the New Seismic Standard applying from June 1, 1981 is an important screening point.
New Seismic Standard
MLIT materials describe it as checking that buildings suffer little damage in roughly upper-5 intensity shaking and do not collapse in roughly upper-6 to 7 intensity shaking. The old standard applies through May 31, 1981.
Purchase checks
Do not rely on construction year alone. Check the building-confirmation timing, structure, seismic diagnosis or retrofit history and management condition. Seismic compliance can also affect safety, financing and resale decisions.
Verification date
Based on primary Japanese government sources checked as of September 2, 2026. Confirm current rules and property-specific documents for each transaction.