How do Japanese patent application publications show dates?

Japanese patent application publications use a unique system for indicating dates. According to MPEP 901.05(a):

“Japanese patent application publications show the date in Arabic numerals by indicating in order the year of the reign of the Emperor, the month, and the day.”

This means that Japanese patent dates are typically formatted as YY.MM.DD, where YY represents the year of the Emperor’s reign, not the Western calendar year.

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Tags: date formats, international patents, japanese patents, Patent Citations