A Comparative Study of US and Japanese Post-Grant
Patent Opposition Systems (*)
Invited Researcher: Kelli Lee LARSON (**)
A key development that has recently occurred in patent harmonization efforts in the US andJapanese patent systems has been the introduction of post-grant patent opposition and review
systems. Generally, post-grant patent opposition and review systems create procedures for third
parties to challenge the validity of patent claims without enduring significant time and expense
spent in litigation, while also help to enhance the reliability of patents by reviewing potentially
defective patents at an early stage thereby helping to stabilize patent rights, increase legal
certainty, and promote innovation. The need for such post-grant patent opposition and review
systems is largely based on patent quality concerns prevalent throughout the US and Japanese
patent systems, as patent examiners face an increasing amount of patents to examine underrestricted budget and time constraints. Such post-grant patent opposition and review systems arealso increasingly important to understand in a globalized world where users of patent systems
frequently conduct cross border business and patent transactions.
However, while the common objectives of the US and Japanese post-grant patent opposition
and review systems are relatively the same, the design of the two systems differ. In the US, throughthe enactment of the America Invents Act (AIA), two significant post-grant patent review systems
were created, the Post-Grant Review (PGR) procedure and the Inter Partes Review (IPR)
procedure. Generally, the Post-Grant Review procedure allows anyone to challenge the validity ofpatent claims within a nine-month window of the patent grant, while Inter Partes Review allows
anyone to challenge the validity of patent claims after the nine-month post-grant review eligibility
window. In Japan, the Patent Act 2014 Amendment re-introduced a post-grant patent opposition
system that came into effect on April 1, 2015 allowing anyone to challenge a patent by writing theiropposition within a six-month time period of the patent grant. Accordingly, this study conducts acomparative examination of the recently implemented US and Japanese post-grant patent
opposition and review systems, highlighting both the substantive and procedural similarities anddifferences, while critically examining the potential implications such post-grant patent opposition
mechanisms may have for users of each respective patent system.

I. Introduction
A key development that has recently occurred in patent harmonization efforts in the US
patent system and the Japanese patent system has been the introduction of post-grant patent
opposition and review systems. 1 Generally, post-grant patent opposition systems allow forprocedures for third parties to challenge the validity of patent claims without enduring significant(*) This is a summary of the report published under the 2016FY Industrial Property Research Promotion Project entrusted by theJapan Patent Office.
(**) PhD Candidate, IP Law, Department of Commercial Law, Hanken School of Economics, at our institute over a period of
approximately 1.5 months from June 27, 2016 through August 20, 2016, as an Invited Researcher for the Fiscal Year 2016.
1 For the sake of brevity, there may be instances in this report that “post-grant opposition” and “post-grant review” is usedinterchangeably. In any case, post-grant opposition and review procedures provide for opportunities for the validity of a patent tobe re-visited.

itime and expense spent in litigation. In the US, the introduction of the America Invents Act (AIA)2
patent reform in 2011 created two significant post-grant patent review procedures called Inter
Partes Review and Post-grant Review effective from September 16, 2012 and March 16, 2013
respectively. In Japan, the Patent Act 2014 Amendment re-introduced a post-grant patent opposition
system that came into effect on April 1, 2015.3 However, there still remains significant proceduraland substantive differences between the post-grant patent opposition and review systems in eachcountry. Due to the newness and increasing popularity of these post-grant proceedings, it is also
important for users of the US and Japanese patent systems to understand such post-grant patentmechanisms in an increasingly globalized world where entities frequently conduct cross borderpatent transactions in commerce. Accordingly, this study conducts a comparative examination of
the recently implemented US and Japanese post-grant patent review and oppositions systems,
highlighting both systems procedural and substantive similarities and differences, while criticallyexamining some of the implications such post-grant patent review and patent opposition systems
may have for the users of each respective patent system.

II. US Post-Grant Patent Review Procedures(1) The Post-Grant Review (PGR) Procedure
The post-grant review procedure is a trial proceeding conducted at the Patent Trial andAppeal Board (PTAB) to review the patentability of one or more claims on any ground that can beraised under § 282(b)(2) or (3). Post-grant review proceedings begin by any party filing a petition
on or prior to the date that is nine months after the grant of the patents or issuance of a reissue
patent.4 Importantly, according to the AIA rules, post-grant review is only available for patents
with a priority date later than March 15, 2013.5 A third party’s review request is instituted upon ashowing that it is more likely than not, that at least one claim challenged is not patentable,6 or thatthe review request raises a novel or unsettled legal question that is important to other patents orpatent applications.7 The patent owner has an opportunity to respond to the petition accordingly.8
The Director of the USPTO (hereinafter the “Director”) shall determine whether to institute a2

Leahy-Smith America Invents Act (AIA), Pub. L. No. 112­29, 125 Stat. 284 (2011) (codified in scattered sections of 35 U.S.C.),
sec. 6(d), § 324(a), 125 Stat. 284, 306.
3 Japanese Ministry of Economy, Trade and Industry Cabinet Decision on the Bill for the Act of the Partial Revision of the Patent
Act (March 11, 2001) (last accessed July 19, 2016) available at http://www.meti.go.jp/english/press/2014/0311_01.html.
4 35 U.S.C. § 321(c).
5 35 U.S.C. § 321 (note) (1)(A).
6 35 U.S.C. § 321(b).
7 35 U.S.C. § 324(b).
8 35 U.S.C. § 323.

ii

post-grant review within three months after receiving a preliminary response to the petition fromthe patent owner,9 or after the last date such response may be filed.10 The determination by the
Director whether to institute such post-grant review is final and not appealable.11 If a post-grant
review is instituted, the petitioner bears the burden of proving invalidity by the standard
preponderance of the evidence. 12 Moreover, post-grant review includes an estoppel effect; 13barring a proceeding before the patent office,14 or a civil action, or a proceeding before theInternational Trade Commission (ITC) with respect to those claim(s) on any ground(s) that wereraised, or reasonably could have raised, during that post-grant review procedure.15 During thepost-grant review procedure, the patent owner may file one motion to amend the patent. Any party
dissatisfied with the decision of the PTAB regarding the post-grant review may appeal the decision
to the Court of Appeals for the Federal Circuit (CAFC).16
One of the benefits of the post-grant review procedure is that it provides an expedited andless expensive opportunity to re-examine recently issued patents compared to patent litigation.17
For instance, the final determination in any post-grant review proceeding instituted should be
issued not later than one year after the date on which the Director notices the post-grant review
procedure, although this time period may be extended up to six months.18 The current cost for a
post-grant review request (up to 20 claims) as of January 1, 2017 is $12,000.00 USD.19 The current
cost for a post-grant post-institution fee (if the Director decides to institute the post-grant review) as
of January 1, 2017 is $18,000.00 USD.20(2) The Inter Partes Review (IPR) Procedure
The inter partes review procedure is an administrative trial proceeding conducted at the
USPTO before the PTAB which reviews the patentability of claims only on grounds that can beraised under sections 102 and 103 of the patent laws on the basis of prior art consisting of patents
935 U.S.C. § 324(c)(1).
35 U.S.C. § 324(c)(2).
11 35 U.S.C. § 324(e).
12 35 U.S.C. § 316(e).
13 However, if the post-grant review is terminated by the petitioner no estoppel will attach to the petitioner or real party in intereston the basis of that petitioner’s institution of that post-grant review. 35 U.S.C. § 327(a).
14 35 U.S.C. § 325(e)(1).
15 35 U.S.C. § 325(e)(2).
16 35 U.S.C. § 329.
17 Patent litigation is extremely expensive in the US. According to the American Intellectual Property Law Association (2013), theaverage cost of a patent lawsuit is approximately $1.6 - $2.8 million US dollars.
18 35 U.S.C. § 326(a)(11). However, this time period may be extended for good cause by a time not more than six months.
19 37 CFR 42.15(b)(1).
20 37 CFR 42.15(b)(2). The post-institution fee represents fees that are paid upfront but are refunded in the event that thepetitioner’s request for post-grant review is denied. However, it ought to be noted that these fees do not take into consideration
attorney fees and other associated fees, thus the total cost of a post-grant review procedure is likely to be substantially higher.
10iiiand printed publications.21 Inter partes review acts somewhat as a hybrid between civil patent
litigation and patent prosecution; its procedure has a more limited discovery process compared tocivil patent litigation, and trials are determined by technically trained judges not juries. Inter partes
review is applicable to proceedings commenced on or after September 16, 2012 as part of the newprovisions of the AIA.22
Generally, a person may file a petition to institute an inter partes review of the patent tocancel as unpatentable one or more claims after the date that is nine months after the grant of apatent, 23 or if a post-grant review is instituted, at the termination of the post-grant review
proceeding. An inter partes review may be instituted upon a showing that there is a reasonable
likelihood that the petitioner would prevail with respect to at least one claim challenged. 24
Furthermore, a petition in writing must identify, with particularity, each claim challenged, thegrounds on which the challenged claim is based, and evidence to support the grounds for eachclaim challenged. The patent owner has an option to file a preliminary response to the petition
within a set time period accordingly.25 The Director will determine whether to institute an interpartes review within three months of receiving a preliminary response from the patent owner.26
The determination by the Director whether to institute an inter partes review if final andnon-appealable.27 If an inter partes review is instituted, the petitioner will have the burden ofproving claims of the patent as unpatentable by a preponderance of the evidence.28
Moreover, inter partes review is subject to an estoppel effect, which bars any petitioner orreal party in interest from requesting or maintaining a proceeding before the USPTO with respect tothat claim on any ground that the petitioner raised or reasonably could have raised during that interpartes review.29 Furthermore, if an inter partes review applied by a petitioner or real party ininterest is instituted, neither party may assert in a civil action in whole or in part, or in a proceeding
before the ITC, that the claim is invalid on any grounds that the petitioner raised or reasonably
could have raised during that inter partes review.30 If an inter partes review is instituted, the patent
owner may file one motion to amend the patent.
As with the post-grant review proceedings, one of the benefits of the inter partes review
procedure is that it provides an expedited and less expensive opportunity to re-examine recently
21

35 U.S.C. § 311(b).
35 U.S.C. § 311.
23 35 U.S.C. § 311(c).
24 35 U.S.C. § 314.
25 35 U.S.C. § 313.
26 35 U.S.C. § § 314(b)(1), 314(b)(2).
27 35 U.S.C. § 314(d).
28 35 U.S.C. § 316(e).
29 35 U.S.C. § 315(e)(1).
30 35 U.S.C. § 315(e)(2).
22

iv

issued patents compared to patent litigation.31 The final determination in any inter partes review
proceeding instituted should be issued not later than one year after the date on which the Director
notices the inter partes review procedure, although this time period may as well be extended by up
to six months.32 The current cost for an inter partes review request (up to 20 claims) as of January
1, 2017 is $9,000.00 USD.33 The current cost for an inter partes review post-institution fee (if the
Director decides to institute the inter partes review) as of January 1, 2017 is $14,000.00 USD.34

III. The Japanese Post-Grant Patent Opposition and Invalidation Trial
Procedures(1) The Trial for Patent Opposition Procedure
The trial for patent opposition procedure is an ex parte administrative trial proceeding
conducted at the Patent Trial and Appeal Department (PTAD) within the Japanese Patent Office(JPO). Proceedings begin by anyone filing an opposition to the patent to the Commissioner of the
Patent Office within six months from the publication of the Gazette containing the patent,35 on
grounds that are limited to those regarding public interest.36 The threshold for instituting a trial forpatent opposition is the reasonable doubt of patentability, and only those claims sought by the
opponent may be considered in the trial examination for opposition.37 Furthermore, what is unique
about the trial for patent opposition proceedings is that they are mainly conducted only on
documentary evidence in principle. 38 A person filing an opposition shall not only state thenecessary grounds for the opposition, but also submit evidence supporting the opposition.39
A Trial Board of three to five examiners examine the patent opposition accordingly.40 If
there are two or more oppositions concerning the same patent the trial examination shall be
combined.41 Once the patent holder has been notified of the reasons for recession by the Chief trial
examiner, the opposition may not be withdrawn.42 Where it is found that a patent concerned in the31

See supra note 17 and accompanying text.
35 U.S.C. § 316(a)(11). However, this time period may be extended for good cause by a time not more than six months.
33 37 CFR 42.15(a)(1).
34 37 CFR 42.15(a)(2). The post-institution fee represents fees that are paid upfront but are refunded in the event that the petitioner’s
request for inter partes review is denied. However, it ought to be noted that these fees do not take into consideration attorney feesand other associated fees, thus the total cost of an inter partes review procedure is likely to be substantially higher.
35 Japan Patent Law, Art. 113.
36 Japan Patent Law, Art. 113(1)(i)(ii)(iii)(iv)(v).
37 Japan Patent Law, Art. 120bis(120-2)(2).
38 Japan Patent Law, Art. 118.
39 Japan Patent Law, Art. 115(1)(iii).
40 Japan Patent Law, Art. 114(1).
41 Japan Patent Law, Art. 120ter(120-3)(1).
42 Japan Patent Law, Art. 120quater(120-4)(1).
32v

opposition falls under any of the items listed in Article 113 of the Japan Patent Law (relating to the
public interest), the trial examiners shall render a ruling that the patent is to be revoked.43 If theruling to revoke has become final and conclusive, the patent right is considered to never haveexisted.44 If the patent in opposition is not found to have fallen under any of the items listed in
Article 113 of the Japan Patent Law, the trial examiners shall rule that the patent is to be
maintained.45
If the trial examiner-in-chief intends to rule to revoke the patent, the patentee will be notified ofthis intention and given an opportunity to submit a response statement within a set time limit.46 The
patentee may also demand that a correction be made to his patent.47 If the patent owner has made ademand for correction, the trial examiner-in-chief will transmit this information to the opponent andallow him an opportunity to submit any counter response within a set time limit.48 Moreover, theparty opposing the patent cannot appeal the PTAD’s Trial Examiners’ decision ruling to the effect thatthe patent right is to be maintained,49 however, they may file separately for a trial for patent
invalidation. The patent owner who received the decision to the effect that the patent right is to berescinded can appeal to the Intellectual Property (IP) High Court with the Commissioner of JPO as
defendant. The duration for the trial for patent opposition proceedings is approximately one year fromthe grant date. As the trial for patent opposition procedure is relatively new, there have only been 5
dispositions as of December 31, 2015.50 The current cost for the trial for patent opposition (as ofApril 1, 2016) is ¥16,500 JPY in addition to ¥2,400 JPY per claim.51(2) The Trial for Patent Invalidation Procedure
The trial for patent invalidation procedure is an inter partes trial proceeding also conductedat the PTAD within JPO, with the purpose of resolving disputes between parties concerning thevalidity of patents. Any interested party may file a request for a trial for patent invalidation any
time after the registration of the patent, and on all grounds available for patent invalidation.52 Even
after the extinguishment of a patent right, a patent invalidation trial may be demanded.53 The
threshold for instituting a trial for patent invalidation is the same as for the trial for patent
43

Japan Patent Law, Art. 114(2).
Japan Patent Law, Art. 114(3).
45 Japan Patent Law, Art. 114(4).
46 Japan Patent Law, Art. 120quinquies(120-5)(1).
47 Japan Patent Law, Art. 120quinquies(120-5)(2)(i)(ii)(iii)(iv).
48 Japan Patent Law, Art. 120quinquies(120-5)(5).
49 Japan Patent Law, Art. 114(5).
50 JPO Status Report 2016, at p.65.
51 Schedule of Japan Patent Office fees (current as April 1, 2016) (last accessed August 5, 2016) available athttps://www.jpo.go.jp/tetuzuki_e/ryoukin_e/ryokine.htm. There may be addition costs, for example, costs for requests forcorrections, appeals, and retrials. Thus, the total cost for the trial for patent opposition procedure may be significantly higher.
52 Japan Patent Law, Art. 123(1)(2).
53 Japan Patent Law, Art. 123(3).
44vi

opposition, the reasonable doubt of patentability. The trial for invalidation proceedings are
conducted mostly by oral proceedings, and the person filing for a trial for invalidation shall not
only state the grounds for invalidating the patent, but also state its relationship with evidence foreach fact required to be proven.54
The Trial Board of three to five examiners examine the patent invalidation request
accordingly. 55 Where there are two or more persons demanding a patent invalidation trial
concerning the same patent right, the demand may be made jointly.56 A demand for a trial may be
withdrawn before the trial decision becomes final.57 However, a demand for a trial may not be
withdrawn after a written reply has been submitted, unless the adverse party consents.58 When atrial has been demanded, or when an amendment has been allowed, the trial examiner-in-chief willtransmit this information to the defendant and will give him an opportunity to submit a written
response within a set time limit.59 Where a trial decision that a patent is to be invalidated has
become final, the patent right shall be deemed to never have existed, 60 while importantly,
upholding the patent triggers an estoppel effect based on the same facts and evidence.61 The patent
owner may also demand a correction trial for making a correction of the description, patentclaim(s), or drawing(s). 62 When a trial for correction has been demanded, the trial
examiner-in-chief will transmit this information to the defendant and will give him an opportunity
to submit a written response within a set time limit.63 Importantly, the examiner-in-chief may
examine even the grounds not pleaded by a party in accordance with certain provisions.64
Moreover, the duration for the trial for patent invalidation proceedings is approximately ten
months from the date of the request and both parties may appeal to the PTAD’s Trial Examiners’
decision to the IP High Court. For the year ending December 31, 2015, there have been 227 filed
requests for trials for patent invalidation, and 234 dispositions.65 The current cost for the trial forpatent invalidation (as of April 1, 2016) is ¥49,500 JPY in addition to ¥5,500 JPY per claim.66

IV. Analysis and Potential Implications of the US and Japanese Post-Grant
54

Japan Patent Law, Art. 131(2).
Japan Patent Law, Art. 137(1).
56 Japan Patent Law, Art. 132(1).
57 Japan Patent Law, Art. 155(1).
58 Japan Patent Law, Art. 155(2).
59 Japan Patent Law, Art. 134(1)(2).
60 Japan Patent Law, Art. 125.
61 Japan Patent Law, Art. 167.
62 Japan Patent Law, Art. 134bis(134-2)(1).
63 Japan Patent Law, Art. 134bis(134-2)(4).
64 Japan Patent Law, Art. 134bis(134-2)(5).
65 JPO Status Report 2016, at pp. 39, 65.
66 Schedule of Japan Patent Office fees (current as April 1, 2016) (last accessed August 5, 2016) available athttps://www.jpo.go.jp/tetuzuki_e/ryoukin_e/ryokine.htm. There may be addition costs, for example, costs for requests forcorrections, appeals, and retrials. Thus, the total cost for the trial for patent invalidation procedure may be significantly higher.
55viiPatent Opposition and Review Systems(1) The US Post-Grant Review System
The post-grant review and the inter partes review procedures generally share the same rules
and functions, however there are a few important differences to describe. Besides the different
time-limitations (post-grant review available during the first nine month-time period following the
grant of the patent, inter partes review being available following the post-grant review period),
post-grant review provides more grounds to challenge patent validity. For instance, any grounds
raised under section 282(b)(2) or (3) of the patent law are challengeable, compared to the interpartes review procedure which is limited to grounds only available under sections 102 and 103 of
the patent law, and only on the basis of prior art consisting of patents or printed publications.
Moreover, there is a slightly higher threshold for instituting a post-grant review procedurecompared to the inter partes review procedure. Post-grant review is instituted upon it being more
likely than not that at least one claim is unpatentable, while an inter partes review procedure is
instituted upon a reasonable likelihood that the patent challenger would prevail on at least one
claim being challenged. Also, the post-grant review procedure has a more limited scope of
discovery, limited to evidence directly related to factual assertions advanced by either of the party’s,
while the scope of discovery for the inter partes review consists of depositions of witnesses, thesubmissions of affidavits or declarations and whatever else is otherwise deemed necessary in theinterest of justice.
Furthermore, in regards to the post-grant review procedures’ relationship to litigation, the US
post-grant review procedures are substitutes for litigation in Federal court. However, the USPTO
and the US district courts, in practice, implement different standards regarding the burden of proof
required when challenging the validity of a patent, and they also apply different standards wheninterpreting patent claims. In US district courts, a patent is presumed valid in litigation,67 while itis not presumed valid at the USPTO during post-grant review procedures. This means that in orderfor someone to challenge a patent’s validity for violating one of the provisions of the Patent Act(novelty, non-obviousness, etc.) in a US district court, they must do so by submitting proof basedon the “clear and convincing” standard of evidence (meaning that the evidence establishes thatsomething is highly and substantially more probable to be true).68 Someone challenging a patent’s
validity at the USPTO has the burden of submitting proof based on the “preponderance of the

67
68

35 U.S.C. § 282.
Microsoft Corp. v. i4i L.P., 131 S. Ct. 2238 (2011).

viii

evidence” standard (more likely than not that there is a claim unpatentable).69 The clear andconvincing standard of evidence is higher than the preponderance of the evidence standard basedon deference to the decision of the USPTO to grant the patent in the first place after considering
any relevant prior art. However, this rationale fails to consider the fact that it is not uncommon forpatent offices to issue defective patents, and that some prior art may have been missed in theexamination process.
Thus, there is an important interplay between the USPTO proceedings and parallel district
court proceedings involving the same patents. Patent office proceedings, both for original
examination and during post-grant proceedings, use the “broadest reasonable interpretation”
standard in claim interpretation,70 meaning the broadest reasonable construction in light of thespecification of the patent in which it appears. While in contrast, district courts construe patentclaims according to the principles articulated by the Federal Circuit in Phillips,71 in which claims
are interpreted by the meaning that a term would have to a person of ordinary skill in the art inquestion at the time of invention.72 Therefore, there is a lack of harmonization over the judicial andadministrative proceedings as there is different interpretative standards for patent claim
construction. In theory, this may lead to diverging decisions on patent validity determination inparallel proceedings at the USPTO and the district court, however, it is likely in these situations
that the district court would stay co-pending patent litigation while post-grant proceedings areunderway. However, this situation still remains uncertain in practice.

69

35 U.S.C. § 316(e).
37 C.F.R. 42.100(b). The broadest reasonable interpretation standard was promulgated by the USPTO by rule, not statute.
71 Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). The validity determination is based on the entire record before
the court taking into consideration both intrinsic and extrinsic evidence.
72 Id.
70ix

(2) The Japanese Post-Grant Opposition and Invalidation System
The Japanese patent system is based on a dual-track system regarding invalidity. This meansthat concerns regarding patent invalidity are dealt with at the patent office through the trial forpatent opposition and the trial for patent invalidation, while there is also the defense of patent
invalidity available in court proceedings. The defense of patent invalidity in essence means that thedefense of invalidity can be raised in an infringement action before the court without regard to
filing an invalidation trial at the patent office.73 Compared to the trial for patent invalidation, thetrial for patent opposition procedure is an ex parte procedure meaning that the proceedings aremainly conducted between the patent office and the patent owner, and conducted only on
documentary evidence, while the trial for patent invalidation is an inter partes proceeding
involving both parties and the patent office. Moreover, anyone can request a trial for patent
opposition procedure within six months of the patent being published in the official Gazette, while
only interested parties may file for a trial for patent invalidation procedure any time after theregistration of a patent. While the trial for patent opposition has only recently been re-introduced,
the trial for patent invalidation has continued to play an important role in the Japanese post-grantsystem.
Regarding the relationship between the post-grant procedures and litigation, a major
development occurred in the year 2000 resulting from the so-called Kilby decision.74 The Kilby
decision essentially empowered judges to invalidate patents during infringement proceedings by
allowing the defense of invalidity to be raised in an infringement action before the court without
regard to filing an invalidation action at JPO. This means that an allegation of invalidity may be
advanced without waiting for a trial decision finding invalidity of the patent to be made final andbinding through the trial procedure for invalidation at JPO. However, the invalidity defense createda situation where parallel invalidity litigation proceedings at JPO and at the IP High Court
potentially may occur simultaneously. Thus, it remains unclear what the procedure would be given
this situation, whether the court would stay proceedings and wait the decision of JPO, or vice versa.
Moreover, if a trial decision is rendered to the effect that the patent right is to be maintained,
the opposing party cannot appeal this decision to the IP High Court. However, if a patent is decided tobe cancelled by JPO, the patent owner may appeal to the IP High Court seeking recession of JPO’s
decision. Thus, depending on the patent challengers’ situation, it may be better to proceed with a trial
for patent opposition or a trial for patent invalidation (however, since 2014, only interested parties
73

See Texas Instruments Inc. v. Fujitsu Ltd. (“Kilby” case), Case No. 1998 (O) – 364 of 1998 (Japanese Supreme Ct., April 11,2000).
74 Id.

xcan request a trial for patent invalidation). For those with a significant interest in the patent andwanting to challenge the validity of the patent anticipating an infringement suit against them,requesting a trial for patent invalidation may be a better option. For those wanting to invalidate
defective patents more so considering their future business strategy and without a significant interestin the patent, the trial for patent opposition procedure will be more appropriate given that a trial forpatent invalidation may not be available due to limited standing. There also appears to be no time
limitation for requesting a trial for invalidation, thus it may be possible to file and withdraw a request
whenever it would appear to be most favorable pursuant to the challenger’s situation.

V. Concluding Remarks
Post-grant patent opposition and review systems clearly play an important role in both the
US and the Japanese patent systems. They not only provide an opportunity for third parties to be
involved in the opposition and re-examination of patent validity at a more cost effective andexpedited rate compared to patent trial litigation, but such systems also help patent offices tostabilize patent rights in a prompter manner. This ought to benefit the public interest in knowing
better not only the boundaries and strength of patents, but it should also help to increase legal
certainty and patent quality, and thereby facilitate innovation.
Post-grant review procedures are somewhat of a double-edged sword in this respect, as they
provide an opportunity for patent offices and third parties to revisit patent validity, but they also
create an element of uncertainty regarding the dispute process for patent owners. Not only do theycreate another mechanism for parties to challenge patents besides in district court, post-grant patent
review procedures essentially do away with entire arduous process that patentees must go throughthat leads to a patent being granted in the first place. The patent was already once inspected by thepatent office, and the certainty of this is gone once it enters the post-grant patent opposition andreview phase. Companies may have made investments and decisions based on that patent being
granted by a patent office in the first instance. While the post-grant patent review procedures in the
US and the patent opposition procedure in Japan are relatively new and have only recently been
implemented, it may be too early to make definitive conclusions regarding their effectiveness on
patent quality concerns. Nevertheless, patent disputes are becoming increasingly complicated anddifficult to resolve along with the advancement of technology, and at the same time, are becoming
more internationalized as corporate actions are increasingly global in nature. It is thus important forcompanies and those organizations that use patents in commerce to become aware of important
post-grant patent opposition and review procedures in order to enhance their understanding of suchmechanisms and to make better informed business decisions regarding their intellectual property.

xi