No “two flies with one flap” in Japan

December 23, 2010

Strict double patenting practice in Japan

1. Global situation – Comparative analysis

Double patenting is the grant of multiple patents for one single invention, which is typically caused by divisional applications. USPTO and EPO have no explicit stipulation regarding the double patenting.

USPTO and EPO provide generous practice regarding the double patenting. US practice has the “Terminal disclaimer” to salvage the double patenting issue based on case laws. This practice enhances the merits of continuation and continuation-in-part applications. EP enlarged board has revealed generous case laws regarding the double patenting compared to Japanese Patent Law.

2. Japanese strict practice – Examination guideline

Japanese Patent Act has Article 39 as the explicit stipulation regarding the double patenting. Japan Patent Office provides a very strict practice with the examination guideline regarding the double patenting based on the Article 39.

Accoding to the examination guideline, two inventions are deemed substantially identical if one subject matter could be created from the other subject matter with a minor change as one of followings unless it brings no new effects.
i) an addition of well-known or commonly used art, 
ii) a deletion of well-known or commonly used art, or 
iii) a replacement with well-known or commonly used art  

3. Practice guideline

Please assess the posibility of double patenting when filing a divisional application before Japan Patent Office very carefully. US continuation and continuation-in-part applications are not available in Japan.

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