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What are the criteria for patentability in your jurisdiction?

The basic criteria for patentability are:

  • subject matter;
  • novelty;
  • inventive step; and
  • industrial applicability.

Subject matter The Patent Act defines an ‘invention’ as "the highly advanced creation of technical ideas by which a law of nature is utilized".

Novelty In line with other regimes, Japanese patent law does not grant exclusionary rights to existing technologies. Article 29(1) of the Patent Act stipulates that inventors may not obtain patents for:

  • inventions that are known to the public (Item i);
  • inventions that are publicly used (Item ii); or
  • inventions that are described in a distributed publication or made publicly available online in Japan or a foreign country before the filing of the patent application (Item iii).

Inventive step If, at the time the application is filed, a person ordinarily skilled in the art could have easily made the invention based on the technology listed in Article 29(1) of the Patent Act (ie, an invention involving the prior art or that is publicly known), the invention cannot be patented (Article 29(2) of the Patent Act).

To reach a decision regarding inventive step, an accurate assessment of the state of the art in the field to which the invention belongs must be made. Further, the points where the invention varies from the prior art must be clearly outlined. While making allowances for the invention’s purpose and effect, a decision will be made regarding whether a person skilled in the art could have easily made the invention by altering the prior art.

Industrial applicability ‘Industry’ is a broad term that includes:

  • manufacture;
  • agriculture;
  • fishing and forestry;
  • mining;
  • commerce; and
  • services.

Medical practice is excluded from the term ‘industry’ and inventions regarding medical treatment are not patentable because they are not industrially applicable. This exclusion stems from the ethical consideration that diagnoses and treatments for humans must not be limited in any way by patents. This legal construction has been adopted due to the lack of statutory provisions expressly denying the validity of patents relating to medical treatment.

However, patents can be obtained for certain aspects of medical treatment, including pharmaceuticals, medical devices and the methods for their manufacture. Article 69(3) of the Patent Act imposes certain limitations on the effect of pharmaceutical patents.

What are the limits on patentability?

Statutory limits to patentability                                   The Japan Patent Act provide certain statutory limitations to patentability. These limitations include:

  • written description requirements;
  • unity requirements;
  • double patenting restrictions;
  • public order restrictions;
  • filing first restrictions; and
  • inventorship requirements.

Limits to double patenting and simultaneous rights Like most other jurisdictions, there is no double patenting in Japan, even if an inventor or an applicant is the same. Unlike in Germany, patent and utility model rights cannot coexist in the same subject matter.

Time limits to patentability In Japan, patents are granted for a 20-year period from the date of filing. In very limited circumstances, patent term extensions are available for drug patents, subject to government delays in approving drugs for patient use.

To what extent can inventions covering software be patented?

Software inventions are patentable if all steps within the invention are tied to hardware. The hardware that executes each step in the procedure must be explicitly stated in the claims (eg, a program that makes a processor execute steps A, B and C).

While the hardware used must be explicitly stated, it can be described in general terms (eg, a processor, computer or processing device). This requirement is easily met when software is executed by a single device. However, if software is executed by multiple devices, it is necessary to identify the machine or module that executes each step (eg, step A is executed by a server computer and step B is executed by a client computer). This ensures that all steps are executed by a machine, not a person.

To what extent can inventions covering business methods be patented?

Business methods are not patentable in Japan. However, business methods are patentable when a software process is realised using hardware (ie, if all steps of a business method are executed by a machine, not a person, the invention is patentable).

To what extent can inventions relating to stem cells be patented?

Inventions relating to stem cells are patentable in Japan. However, inventions that contravene public order, morality or public health are not patentable. When an invention involves a step that destroys an embryo, it will be rejected under Article 32 of the Patent Act. However, inventions relating to the culturing or differentiation of an established embryonic stem cell line are patentable. This, along with other factors, has led to prolific studies and development in induced pluripotent stem cell technology in Japan. 

Are there restrictions on any other kinds of invention?

Inventions relating to the medical treatment of humans are not patentable. The Patent Office has deemed that medical practice on humans is not industrially applicable and thus cannot be patented. Accordingly, the examination guidelines expressly state that surgical or therapeutic treatment methods concerning humans and methods of diagnosis applied to humans are not patentable.

However, in 2002 the Tokyo High Court issued a controversial decision which implicitly recommended that the protection of medical practice under the Patent Act to be reconsidered. This topic is still being discussed and has reached the Japanese cabinet on several occasions.

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