16 Study on the Doctrine of Equivalents in Patent
Infringement―Focus on Laws and Practices Comparison
China and JapanWen Jun Yan(*)
How to define the scope of patent protection rationally is an important problem with regard to the patent
system. The doctrine of equivalents plays an important role in defining the scope of patent protection and has
already been accepted and applied in both China and Japan. The doctrines of equivalents of China and Japan
have areas in common as well as areas that differ. Based on legal provisions and administration of justice, thispaper compares the doctrine of equivalents between China and Japan.
The main content of this paper includes the relevant legal provisions of the two countries, the history of thedoctrine of equivalents and an overview of the practice of this doctrine, the requisites of this doctrine, theapplications of this doctrine adopted by the court, and the party's burden of proof related to the doctrine ofequivalents in action for infringement of a patent.

1

Relevant statutory provisions on thedoctrine of equivalents

At present, there is no clear statutory
provision on the doctrine of equivalents on patentrights in either China or Japan. The relevant
regulation in Japan is Article 70 of the Japanese
patent law and in China is Article 56 (1) of theChinese patent law.
Although there is no consistency in the legal
construction and use of language in theabove-mentioned regulations of the two countries,
the legal principle and meaning of the regulations
are basically the same, confirming that the patentclaims formulate the basis of ascertaining thescope of protection, whilst the patent
specifications and associated diagrams are usedfor explaining the rights of the patent. Based onthe aforementioned requirements, it follows thatthe existence of the doctrine of equivalents isessential as well as possible.
2History and overview of the doctrine ofequivalents

In Japan, the application of said principle canbe divided into three stages: Before 1959, where
the principle did not exist and there were nojudgments. From 1959 to February 1998, where
the principle was finally accepted after various
debates and passive application. After February
1998, whereby the Japanese Supreme Court
applied said principle in the “Ball Spline” case.
In China, the application of the said principle
can be divided into two stages: From April 1, 1984
to June 2001, where although such a principle had(*)

been widely accepted for use by the academics
and practitioners, there was no standardized wayof applying the principle. After July 2001, courtsof law at all levels had applied the principle basedon the directive entitled “Several regulations on
handling the applicable legal questions on patentdisputes” issued by the Supreme People's Court.
3(1) Non-essential part
The first requirement is “the non-essentialpart” as indicated by the Japanese Supreme Courtin their judgment which states that “the differentparts are not essential parts of the patented
invention.” “Essential part” does not refer to thecomposition of different parts of the patented
invention but to the innovative technical idea ofthe patented invention.
In the judicial explanation of the Supreme
People’s Court of China, there is no regulation ofconcerning “non-essential part,” but there is aconnection with this is in “with basically the samemeans.” “Basically the same means” concerns
the technical characteristics, but the court isoccasionally deals with whether the means thatthe patented technology adopts is the same withthe accused infringer.
If the means of the accused infringer and thepatented technology are compared at the sametime, there is a similarity in this requirement
between the two countries. But if the means of
the technical characteristics are compared,“basically the same means” and “non- essentialpart” have obvious differences. This requirement
is the greatest obstacle to equating with thisJudge, People's High Court of Shandong Province

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Requirements of the Principle● 122 ●doctrine in Japan. In China there are too few
cases that are equivalent because of means.
(2) Possibility of Interchangeability
The second requirement is assumed up as“possibility of interchangeability.” The JapaneseSupreme Court points out in its judgments,“Different parts can be replaced with thecorresponding part in the patented invention,
producing the same operation and effect, andrealizing the same purpose.” This means that
“operation and effect” are the same; after being
replaced by different parts, the operation andeffect of the whole technical scheme is the sameand can still realize the purpose of the invention.
One of the requirements stipulated in the
judicial explanation of the Supreme People'sCourt of China that equates characteristics is thatthe technical characteristic recorded with thepatent claim “realize basically the same function,
obtain basically the same result.” While assertingwhether the function and result are basically thesame, the court generally considers thecharacteristic function and result of patented
technology in the purpose of realizing the patent,
because often the accused infringing technology
is compared with the results of patented
technology.
The one thing in common with Japan andChina is “operation and effect (function).” Thedifference lies in the fact that Japan emphasizes
the realization of the purpose of invention, while
Chinese courts must consider the function andresult due to changes to the technicalcharacteristics, and this has caused a dispute
regarding “improvements.”(3) Ease of Interchangeability
The third requirement is summed up as“ease of interchangeability.” The JapaneseSupreme Court points out, “the above-mentioned
replacement is easy to think of for a person
skilled in the art.” To assert ease ofinterchangeability, the standard for a person
skilled in the art is an ordinary technical staff inthis field, generally the level of an averageengineer. The time is when the infringing
products are made. The technical standard is easy
to think for a person skilled in the art without a
lot of effort.
One of the requirements stipulating in
judicial explanation of the Supreme People's
Court of China which equate the characteristics isthe “characteristic that a person skilled in the art
does not need creative efforts to think of.” The
standard is the range of an ordinary technical staff,
the technical level is that requiring creative
efforts and the time, although not stipulated, isgenerally in practice the time that the accused
infringer is manufactured.

It is obvious, from looking at the standards,
this requirement is very similar in both China andJapan; the result with very few denied by thisrequirement alone.
(4) Non-prior art
The fourth requirement is summed up as“non-prior art". The Japanese Supreme Court
points out in judgments, “technology used in
infringing products are different from prior art
used in the patented invention on the application
date or different from technology, easily derived
by a person skilled in the art.” The subject of thiscomparison in non-prior art is the accusedtechnology but not the replacement part. It is
generally acknowledged that this technology fits
the progressing standard.
There is no clear definition about thenon-prior art in the judicial explanation of theSupreme People’s Courts of China. But defense ofprior art plays the same role. If the accused
infringer is closer to the prior art and has certain
differences with the patented one, then no
infringement is established.
According to the purpose and result, thisrequirement in both China and Japan are basicallythe same. Its difference lies in that, first, Japan
compares the accused technology with the priorart, whereas China compares the accusedtechnology with the prior art and the patented
technology respectively. Second, Japan regards
the prior art as the prerequisite while China takes
it as a counterplea for non infringement.
(5) Special circumstances and estoppel
The fifth requirement is summed up as“special circumstances”. The Japanese Supreme
Court points out in its judgments that “There areno special circumstances that consciously remove
the accused infringer from the patent claim in theprocess of filing.”
There are none of the aforementioned items
stipulated in the judicial explanation of theSupreme People's Court of China. However,
estoppel is generally accepted by the courts andused in practice.
The “conscious exclusion” in Japan is very
similar to “estoppel” in China. But “consciousexclusion” mentioned by the Japanese Supreme
Court is only one type of “special circumstance.”
4

Application of Doctrine of equivalentsin judicial proceedings(1) Is the application of the doctrine ofequivalents
fundamentalor
anexception?
In Japan, it is an exception. Basically, only
when the party makes a clear demand will thejudge consider the application of the doctrine of● 123 ●IIP Bulletin 2005

equivalents.
In the judicial explanation of the Supreme
People’s Court of China, the scope of patent
protection includes the corresponding equivalenttechnical features related to the patent claim. In
this way, the doctrine is regarded as fundamental.
(2) Order of requirements when the court
adopts the doctrine of equivalents
The order of requirements which are usedby the Japanese courts are the second, the first,
the third and then the fourth and fifth, whereby
the fourth and fifth are only used when one party
makes a demand.
In China, first, the court considers if thefunctions and results are the same; if the means
are the same; if it can be easily thought of by aperson skilled in the art without any creative
effort; Then, when the accused infringer makes ademand, it is determined whether there isestoppel as well as if the defense is tenable ornot.
(3) Is it possible to neglect acknowledged
equivalent technical characteristics inthe patent claim?
Japanemphasizes
equating
every
composition in the claim. However, there is atheory known as “incomplete use.” Up to now,
this theory hasn’t been completely denied, but it
generally isn’t applied by the courts.
In China, the judicial explanation of theSupreme People's Court of China emphasizes
equating the technical characteristics also, but
China has the principle of “surplus designation”.
Whether this principle is acknowledged requires
further discussion.
(4) Technical judgment in the process ofapplying the Doctrine of Equivalents
In Japan, there is an investigating officer
system, special committee system and anappraisement system, which can be used to help
the judge solve technical issues in patent related
judgments.
In China, there is an investing officer
system, expert consultation and the juror system,
which can be used to help the judge solve
technical issues in patent related judgments.
5

A party’s claim of the doctrine ofequivalents and the burden of proof in
the course of a lawsuit(1) A party’s obligation to claim thedoctrine of equivalents in a patent
related action
Japanese courts regard the doctrine ofequivalents as an “exception”. The patentee
should declare the use of the doctrine voluntarily.

IIP Bulletin 2005

The Chinese court regards it as “fundamental.”
Even if the patentee does not declare, the court
may apply the doctrine automatically.
(2) A party’s burden of proof in the patent
related action when the doctrine ofequivalents is adopted
In Japan, the fist to third requirements
should be proven by the patentee, and the fourthand fifth requirements should be proven by theaccused infringer. In China, the two requirements,stipulated in the judicial explanation by theSupreme People's Court, should be proven by thepatentee. The estoppel and the defense of priorart should be proven by the accused infringer.
(3) Theinfluence
ofa
defendant’sindependent development on thedoctrine of equivalents.
In Japan, basically, it is not recognized thatindependent development will influence thedoctrine. But it has been said that independent
development can fall under the fifth requirementof “special circumstances.” In China, it isgenerally acknowledged, that independent
development won’t influence the application ofthe doctrine.
6Conclusion and several issues(1) Conclusion
The provisions on the scope of patent
protection (or range of patented technology) are
quite similar both in Chinese and Japanese law.
These are the legal foundations of the doctrine ofequivalents and also the reason why the doctrine
was made. Though each country has a different
application history of the doctrine, both countries
now recognize the doctrine of equivalents. The
requirements of the doctrine of equivalents wereestablished through the judgments of theSupreme Court in Japan and through the judicial
explanation in China. Regarding the requirementsof the doctrine, the Japanese requirements two,
three and five are basically the same as theChinese judicial explanation and judicial practice:requirement four has a certain difference andrequirement one has an obvious difference. With
regard to applying the doctrine of equivalents, it
is regarded as fundamental in China and as theexception in Japan. But the order of applying thedoctrine are similar in both countries.
Concerning each party’s burden of proof , themethods used in both countries are basically thesame.
(2) Several issues
The first issue is whether the doctrine ofequivalents and its requirements will change inthe future. It would not be impossible to make● 124 ●

the standard of the doctrine of equivalents
protect the interests of third parties in the future.
The second issue is how to solve technicalissues rationally. The question of how to enable
the judge to make an efficient decision, and how
to convey the opinion of the technical assistant as
opposed to the name of the judge, are stillquestions for both countries to solve
The third issue is how to maintain aconsistent standard when applying the doctrineof equivalents. The Japanese method ofconcentrating administration of patent cases is agood example for China to study..
The Fourth issue is whether China should
adopt a stricter standard for the doctrine ofequivalents. In the situation that China isrelatively behind scientifically and technically,
begs further discussion on whether a stricter
standard for the doctrine of equivalents isrequired.

● 125 ●IIP Bulletin 2005