The Maxacalcitol case in Japan; broader protection for a “significant” invention under the doctrine of equivalence?

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In Japan, a very important judgment concerning the doctrine of equivalents has recently been handed down; i.e., the Maxacalcitol judgment by the IP High Court. Although the judgment was appealed and is currently pending at the Supreme Court, it is likely that the judgment of the IP High Court will be upheld. If the judgment becomes final, it would be much easier for a “significant” invention to be protected under the doctrine of equivalents.

The first affirmative judgment based on the doctrine of equivalents under Japanese patent law was the Ball Spline Bearing case of the Supreme Court in 1998, in which the court established five requirements (See “Further information” at the end) for infringement under the doctrine of equivalents. However, it should be noted that there are very few cases where Japanese courts have affirmed infringement based on the doctrine of equivalents. It has been reported that the first requirement of the doctrine of equivalents was the main reason of dismissal (in more than 70 percent of dismissed cases).

The meaning of the first requirement is that if the differing part of the claim compared to the allegedly infringing product/process is an essential part of the patented invention, the allegedly infringing product/process is considered to be a totally different invention because it has adopted a different technical feature with regard to an essential part of the patented invention. In order to get a better understanding of the case, the concept of the “technical idea” has been used by the courts. For the first requirement to be satisfied, the technical idea of the allegedly infringing product/process as a whole must still be within that of the patented invention, which means that no “essential element” is changed, and there could potentially be infringing under the doctrine of equivalents.

After the Ball Spline Bearing case the courts have, in determining the technical idea of the patented invention with regard to the first requirement, usually followed the actual wordings in the claim. The problem of this approach is that the technical idea of the patented invention interpreted from the actual wordings in the claim is so narrow that even if the allegedly infringing product/process is very slightly different from the claim it is considered not to fall under the technical idea of the patented invention (See Fig.1). As the allegedly infringing product/process, in practice, often adopts some different technical features from the actual wordings in the claim, it has been criticized that the protection under the doctrine of equivalents is too weak.

Fig. 1 (Traditional approach after Ball Spline Bearing case)

  elements the first requirement
claim of the patented invention A + B + C It is likely that the courts determine the technical idea of the patented invention as almost identical to the claim: A + B + C. Therefore, the allegedly infringing product/process: A + B + C’ does NOT usually fall under the technical idea of the patented invention.
the allegedly infringing product/process A + B + C’

However, in the Maxacalcitol case, this traditional approach was clearly rejected, holding that the courts should take into account the degree of the contribution of the patented invention over prior art at the priority date. It held that if the patented invention makes a “significant” contribution over prior art, the technical idea thereof should be recognized as a more generic one beyond the actual wordings in the claim. As a result, because of this broader interpretation of the technical idea of the patented invention, it would be much easier for the allegedly infringing product/process to fall under the technical idea of the patented invention (See Fig. 2).

Fig. 2 (The approach by IP High Court: in case there is a “significant” contribution over prior art)

  elements the first requirement
claim of the patented invention A + B + C If the patented invention makes a “significant” contribution over prior art, it is likely that the courts determine the technical idea of the patented invention beyond the claim, such as A + B + G(C). Here, G(C) is a generic concept of C that also includes C’ as its subordinate concept. Therefore, the allegedly infringing product/process: A + B + C’ falls under the technical idea of the patented invention.
the allegedly infringing product/process A + B + C’

If the patented invention does not make a “significant” contribution over prior art, the technical idea thereof should be recognized as almost literary the actual wordings in the claim (like traditional approach). Therefore, it is likely that the allegedly infringing product/process is considered not to fall under the technical idea of the patented invention.

In summary, it is expected there will be more cases where Japanese courts have affirmed infringement based on the doctrine of equivalents if the patented invention does make a “significant” contribution over prior art. Regarding the standard of a “significant” contribution, further case law is to be expected in the future to clarify this concept.

In practice, it is necessary to pay more attention to the possibility of doctrine of equivalents, taking into account the extent of the contribution that the patented invention makes over prior art. It is not an exaggeration to state that the application of the doctrine of equivalents may remarkably change if the judgment in the Maxacalcitol case becomes final.

2016-10-08

Hirotaka Nonaka


Further information: The five requirements of the doctrine of equivalents in Japan

The followings are the five requirements in Ball Spline Bearing case, which have subsequently been followed in later case law.

Even if there is a differing part in the claim (hereinafter referred as “the Difference” or “the Different Part”) from the allegedly infringing product/process (hereinafter referred simply as “the Product”), it is valid to consider that “the Product” constitutes an infringement under the doctrine of equivalents in case the following five requirements are satisfied:

(1) Non-essential part

 “The Difference” is not an essential part of the patented invention.

(2) Possibility of interchangeability

 Even when “the Different Part” is interchanged by the corresponding part of “the Product”, it could achieve the purpose of the patented invention, and would produce the same function and same effect with the patented invention.

 (3) Ease of interchangeability

 The person in the ordinary skill in the art could easily come up with the idea of changing “the Different Part” with the corresponding part of “the Product” at the time “the Product” was manufactured/used.

 (4) Not part of the prior art

 “The Product” is neither identical to nor obvious from the prior art at the priority date of the patent application.

 (5) No special circumstance

 There is no special circumstance such as the estoppel in which “the Product” is intentionally excluded from the scope of the claim during the prosecution history by the patentee.

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