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Tips of Performing Japanese Patent Numbers Search

Japanese patent numbering system is very tricky, and confusion, because application number, laid-open publication number, examination number, and granted patent number are all different for the same Japanese patent application. Furthermore, Japanese patent numbering system uses 2 different Emperor Years and one Western Year in the numbering, which often cause confusion if one is not familiar with the system.

Lain-open publication number

When searching for a Japanese patent prior to 2000, the Emperor Years are used in the patent number. The Emperor Year was set to 1 in 1989 when the current emperor took the throne. Since 1989, the Emperor Year is called Heisei. If you see a Japanese patent with H01-xxxxx, H05-yyyyy, etc., it means that this patent is filed or published after 1989. However, 1989 is also the last year of Shouwa, Shouwa 64, which is the previous Emperor year. If you cannot find the right document by using H01-xxxxx in a patent no search, please try S64-xxxxx.

In short, there are at least 3 numbering systems relating to year of filing or publication:

  • If a Japanese patent is filed or published before 1989, the number has the format: Sxx-yyyyyy or JPxx-yyyyy, in which xx is 64 or less.
  • If a patent is filed or published after 1989 and before 2000, then the number has the format: Hxx-yyyyyy or JPxx-yyyyyy, in which xx is between 1 (for 1989) and 11 (for 1999).
  • For a patent that is filed or published in 2000 or after, the number format is JP20xx-yyyyyy.

An unexamined Japanese patent application (called 'Kokai') is published in 18 months after its earliest priority date (laid-open). Japanese patent Kokai numbers (laid-open publication number) have a suffix A. A typical JPO unexamined patent issued before 1999 would have a number like this: JPxx-yyyyyy or Sxx-yyyyyy or Hxx-yyyyyy, in which xx is a number either between 1 and 11, or is a number that is less than 64.

Examined Japanese patent documents

An examined Japanese patent is published pre-grant. This second publication stage is called "kokoku". The Kokoku numbers are similar to laid-open publication number but with a suffix B, for example JP08-567980B, or H06-674905B.

Registered Patent Numbers

An unopposed Japanese patent would be assigned a seven digit registration number, for example JP3678945.




Patent numbers search in Japanese is confusion because of the complexity of numbering system.

Please feel free to contact us shall you need any assistance in searching for a Japanese patent.


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