Same Twelve Months, Different Clock: Translating Patent Grace Periods Between the United States and Japan

Executive Summary:  The United States and Japan each offer a one-year route around certain patent-defeating disclosures. That shared duration is useful—and dangerously incomplete. The U.S. rule asks whether a disclosure falls within a source- and subject-matter-based exception to prior art measured from the claimed invention’s effective filing date. Japan’s rule asks whether a disclosure that would otherwise defeat novelty or inventive step qualifies for a statutory exception tied to the person holding the right to obtain a patent, followed by a Japanese or PCT filing and, when the applicant proceeds under Article 30(2)’s right-holder-act route, prescribed statement-and-proof procedures. 35 U.S.C. §§ 100(i), 102(a)(1), (b)(1) (2018); Tokkyo-hō [Patent Act], Law No. 121 of 1959, arts. 29–30 (Japan

I.                   Introduction

In discussing U.S. law, “disclosure” is sometimes used here in the statutory sense to include any relevant § 102(a)(1) event, including a commercial sale. The term does not necessarily mean that technical information was made available to the public. See 35 U.S.C. § 102(a)(1), (b)(1); Sanho Corp. v. Kaijet Technology International Ltd., Inc., 108 F.4th 1376, 1380–82 (Fed. Cir. 2024).

Those are not two versions of the same safe harbor. They are different legal mechanisms that happen to use the same outer period. A practitioner who translates “one year” without translating the event, actor, filing anchor, subject matter, and procedure risks giving the client exactly the wrong deadline.

Consider a Tokyo startup that presents Feature A of a new sensor on January 15, files a U.S. provisional application covering Feature A on May 1, and waits until the following May 1 to file a U.S. nonprovisional and a Japanese application. The U.S. claims may have an effective filing date of the first May 1 if the provisional adequately supports them; the January presentation would then be less than one year before that effective filing date. Japan, by contrast, ordinarily asks whether the application in Japan—or a qualifying PCT international application—was filed within one year of the January disclosure. A Paris priority claim to the U.S. provisional does not substitute its date for the later Japanese filing date in applying Article 30. See 35 U.S.C. §§ 100(i)(1)(B), 119(e); 2024 JPO Applicant Guide, supra, at 15; 2024 JPO Q&A, supra, at 18–19; 2020 Provisional English Guidelines, supra, at 14–15. Same disclosure, same nominal year, opposite possible results.

The most reliable way to translate the two systems is to pass every event through five questions: What event needs an exception? Whose act or information is involved? From which filing date is the year measured? How much subject matter is protected, including against intervening third parties? What must be filed or proved? These “five gates” are a comparative tool, not a statutory test.

II.                The Vocabulary Bridge

Axis	United States	Japan
Basic mechanism	Exceptions that remove specified disclosures from § 102 prior art	Exception that treats a qualifying disclosure as not falling within Article 29(1) for Article 29 novelty and inventive-step analysis
Outer period	One year or less before the claimed invention’s effective filing date	Application filed within one year after the qualifying disclosure
Principal actor inquiry	Inventor origin, derivation from an inventor, or a qualifying prior public disclosure	Article 30(2) right-holder-act route, or Article 30(1) contrary-to-intention route
Filing anchor	Claim by claim; earliest application supporting the claimed invention as a whole	Actual Japanese filing or qualifying PCT international filing; foreign priority does not replace that filing date for Article 30
Filing formalities	No universal grace-period claim at filing; proof can arise during examination	Ordinary Japanese national application: statement at filing and proof within thirty days. PCT application: special Article 184-14 national-phase timing; a qualifying Rule 4.17(v) declaration may satisfy the statement requirement
Independent intervening art	Within the one-year interval, sometimes removed for previously publicly disclosed, matching subject matter	Generally remains capable of defeating the application
Earlier-filed patent documents	Separate source and prior-public-disclosure exceptions may apply	Article 30 does not displace Article 29-2 or first-to-file rules
Geographic location of triggering event	Events in the United States or abroad may qualify as prior art	Events in Japan or a foreign country may fall within Article 29(1)
Territorial effect of exception	Determines U.S. patentability only	Determines Japanese patentability only

Comparative shorthand only; each event still requires country-specific analysis.

The location of the event and the territorial effect of the exception are separate concepts. Both systems can reach events occurring abroad; each exception affects patentability only under the law that creates it. See 35 U.S.C. § 102(a)(1); Patent Act arts. 29, para. 1, 30. The table supplies a translation map, but not a filing opinion. Each axis requires its own analysis.

III.             Gate One: What Event Needs the Exception?

A.                 United States: start with the prior-art category

Section 102(a)(1) reaches a claimed invention that, before its effective filing date, was patented, described in a printed publication, in public use, on sale, or otherwise available to the public. The geography is not limited to the United States. 35 U.S.C. § 102(a)(1). The grace-period inquiry therefore begins by identifying the asserted prior-art event and the subject matter it disclosed—not merely by recording that the inventor “announced” something.

The categories do not all require public technical teaching in the same way. A commercial sale or offer for sale may trigger the U.S. on-sale bar even when the invention’s technical details have not been disclosed to the public. Helsinn Healthcare S.A. v. Teva Pharmaceuticals USA, Inc., 586 U.S. 123, 129–32 (2019). The familiar two-part on-sale framework asks whether, before the critical date, the invention was the subject of a commercial offer for sale and was ready for patenting. Pfaff v. Wells Electronics, Inc., 525 U.S. 55, 67–68 (1998). The Federal Circuit has also held that commercial sales of products manufactured through a secret claimed process can place that process on sale under the AIA. Celanese International Corp. v. International Trade Commission, 111 F.4th 1338, 1344–49 (Fed. Cir. 2024), cert. denied, 145 S. Ct. 1961 (2025).

That point is especially important for Japanese counsel accustomed to asking whether a sale made the invention publicly known or publicly worked. In the United States, a commercial transaction may require a grace-period analysis even when confidentiality prevents the public from learning the technical details. An experimental-use analysis, the character of the transaction, and whether the invention was ready for patenting may still matter, but “the technology remained secret” is not by itself an answer.

Once an event falls within § 102(a)(1), § 102(b)(1)(A) removes it as prior art if it occurred one year or less before the claimed invention’s effective filing date and was made by the inventor or joint inventor, or by another who obtained the disclosed subject matter directly or indirectly from an inventor. 35 U.S.C. § 102(b)(1)(A). In practical shorthand, this is the inventor-originated exception. The shorthand should not obscure two separate proofs: the event must fall within the one-year interval, and its relevant subject matter must trace to an inventor.

B.                 Japan: start with Article 29, then ask whether Article 30 neutralizes the event

Article 29(1) covers an invention that, before filing, was publicly known, publicly worked, described in a distributed publication, or made publicly available through a telecommunications line, in Japan or abroad. Article 29(2) supplies the inventive-step consequence of the prior art. Patent Act art. 29, paras. 1–2. Article 30 does not erase history or award an earlier filing date. For the claimed invention in the application, it directs that a qualifying event be treated as though it had not fallen within Article 29(1) when applying Article 29(1) and (2). Id. art. 30, paras. 1–2.

The covered forms of disclosure are correspondingly broad. Depending on what became public, Article 30 can reach technical papers, journal or website postings, conference talks, demonstrations, exhibitions, customer presentations, broadcasts, sales, and public working. 2024 JPO Applicant Guide, supra, at 5–9, 28–30; 2020 Provisional English Guidelines, supra, at 5–13. But a sale is relevant only insofar as it brings the invention within an Article 29(1) category. The absence of advertising or a public technical explanation is relevant but not necessarily dispositive. Under JPO guidance, the inquiry turns on whether the invention’s contents became known to unspecified persons without an obligation of secrecy or whether the invention was worked under conditions in which those contents were, or were likely to become, publicly known. Counsel should therefore examine what purchasers, users, attendees, or other members of the relevant public could obtain from the transaction, the product, or its resulting use. Patent Act art. 29, para. 1(i)–(ii); 2024 JPO Applicant Guide, supra, at 8–9; 2024 JPO Q&A, supra, at 8–9; 2020 Provisional English Guidelines, supra, at 8 n.1. This contrasts with the U.S. treatment of commercial sales whose technical details remain secret.

The August 2024 materials add practice-specific clarifications. When an email newsletter constitutes a qualifying disclosure, the proving document may identify the message without listing every recipient. A geographically defined mass sale may be documented as a single disclosure act without naming every store. Conversely, an explanation during negotiations with a specifically limited group of customers ordinarily does not make the invention publicly known when nondisclosure is expressly or implicitly expected. 2024 JPO Applicant Guide, supra, at 7–9, 28–30; 2024 JPO Q&A, supra, at 9, 15–16.

The Article 30(2) right-holder-act route—often described as the voluntary-disclosure route—focuses on an invention that became public because of an act of the person holding the right to obtain a patent. Patent Act art. 30, para. 2. The statutory text excludes loss of novelty resulting from publication in a gazette concerning an invention, utility model, design, or trademark. Id. Article 30 is therefore not a general device for neutralizing the publication of an earlier patent filing.

The Article 30(1) contrary-to-intention route separately covers a disclosure contrary to the intention of the person holding the right to obtain the patent—for example, a leak despite a confidentiality agreement or disclosure through intimidation or espionage. Id. art. 30, para. 1; 2024 JPO Applicant Guide, supra, at 15; 2024 JPO Q&A, supra, at 19; 2020 Provisional English Guidelines, supra, at 16–17. Both routes retain the one-year filing requirement, but their procedural treatment differs substantially.

IV.            Gate Two: Whose Disclosure Is It?

A.                 United States: origin can matter more than the name on the document

Section 102(b)(1)(A) is not confined to a paper carrying an inventor’s byline. It also covers a disclosure by someone who obtained the subject matter, directly or indirectly, from an inventor. 35 U.S.C. § 102(b)(1)(A). That can matter when a distributor republishes a product sheet, a journalist reports a technical briefing, or an NDA recipient leaks material. The legal question is whether the relevant disclosed subject matter originated with an inventor and whether the evidentiary chain supports that conclusion.

The exception is not an invitation to “swear behind” genuinely independent prior art by proving an earlier date of conception. Under the AIA’s first-inventor-to-file structure, earlier invention alone does not remove an independent disclosure. If the third party independently developed the subject matter, the applicant needs a different statutory path—most notably the narrow prior-public-disclosure route discussed below—or the third-party reference remains prior art. See 35 U.S.C. §§ 102(a)–(b); Sanho Corp. v. Kaijet Technology International Ltd., Inc., 108 F.4th 1376, 1380–82 (Fed. Cir. 2024).

The practical proof file should therefore capture who communicated what to whom, on what date, under what terms, and how the public-facing disclosure was generated. Inventor declarations, dated drafts, emails transmitting technical materials, website archives, meeting records, and agreements can turn an assertion of origin into an admissible narrative.

B.                 Japan: track the holder of the right to obtain the patent

Japan’s Article 30 vocabulary is entitlement-centered. The Article 30(2) right-holder-act route asks whether public availability resulted from an act of the person holding the right to obtain a patent. The proving document should establish the facts of the disclosure and the succession of the right, including the relationship among inventor, right holder at disclosure, discloser, and applicant. Patent Act arts. 30, para. 2, 33; 2024 JPO Applicant Guide, supra, at 7–12; 2020 Provisional English Guidelines, supra, at 7–12.

This framing is familiar to Japanese practitioners but easy for U.S. counsel to flatten into “an inventor disclosure.” That translation can fail when an employee, university, startup, sponsor, or successor is involved. Succession after the disclosure may establish the applicant’s entitlement because the right to obtain a patent is transferable. Patent Act art. 33, para. 1. The Article 30 proving record, however, should identify the inventor, the person holding the right to obtain a patent when the act causing publication occurred, the person who published the invention, and the applicant, and should state each transfer connecting the inventor through the then-current right holder to the applicant. 2024 JPO Applicant Guide, supra, at 10–12; 2020 Provisional English Guidelines, supra, at 10–12. The JPO does not require submission of the written assignment itself when those statements conform to the facts. 2024 JPO Applicant Guide, supra, at 10–11; 2020 Provisional English Guidelines, supra, at 10–11.

For the Article 30(1) contrary-to-intention route, preserve facts showing why the act was contrary to the right holder’s intention. A confidentiality agreement is highly useful, but the evidence should extend to the disclosure itself: the recipient, protected material, contractual restriction, date and mode of leak, and the overlap between the leaked content and the claims. Article 30(1) does not eliminate the one-year filing deadline simply because the disclosure was wrongful. Patent Act art. 30, para. 1; 2024 JPO Applicant Guide, supra, at 15; 2024 JPO Q&A, supra, at 19.

V.               Gate Three: Which Filing Date Anchors the Year?

This is the central cross-border difference.

A.                 The U.S. year is measured from the effective filing date of the claimed invention

Section 102(b)(1) looks backward one year from “the effective filing date of the claimed invention.” 35 U.S.C. § 102(b)(1). The effective filing date is determined claim by claim and depends on whether the earlier application supports the claimed invention as a whole under the applicable priority and benefit requirements. It may be the actual U.S. filing date or the earliest date to which the claim is entitled through a properly supported priority or benefit claim, including a foreign priority claim or a provisional application. Id. §§ 100(i), 119(a), 119(e); U.S. Patent & Trademark Off., Manual of Patent Examining Procedure §§ 2152, 2152.01 (9th ed. Rev. 01.2024, Nov. 2024) [hereinafter MPEP].

Support is the hinge. A priority application that describes Feature A does not necessarily supply the effective filing date for a later claim requiring A+B. The public disclosure must be compared with each claim, and the priority document must be tested under the applicable written-description and enablement standards for the claimed subject matter. A single application can therefore contain claims with different effective filing dates and different grace-period outcomes.

Return to the January 15 presentation, May 1 U.S. provisional, and next-May-1 nonprovisional. A claim fully supported by the provisional can have the first May 1 as its effective filing date. The January 15 disclosure is only a few months before that date even though the nonprovisional arrived more than a year after the disclosure. A later claim to A+B, where B appears only in the nonprovisional, may have the second May 1 as its effective filing date; for that claim, the same January event may be outside the year if it disclosed B.

This is why a U.S. lawyer can truthfully say that a filing made more than twelve calendar months after a disclosure may still survive under the U.S. rule. The statement is safe only after adding “for claims entitled to an effective filing date no more than one year after that disclosure.”

B.                 Japan generally requires the Japanese or PCT filing itself within one year

Article 30 asks whether the person holding the right filed the patent application within one year after the disclosure. Patent Act art. 30, paras. 1–2. For an application claiming Paris Convention priority, JPO guidance states that the patent application must be filed in Japan within one year from publication of the invention. 2024 JPO Applicant Guide, supra, at 15; 2024 JPO Q&A, supra, at 19; 2020 Provisional English Guidelines, supra, at 14. The foreign priority date does not replace the later Japanese filing date for satisfying Article 30.

This point is limited to Article 30’s one-year filing requirement. A valid Paris priority claim may still establish the relevant date for ordinary novelty and inventive-step analysis in Japan as to subject matter supported by the priority application. Japan Patent Off., Patent, FAQ 6-8, https://www.jpo.go.jp/e/faq/yokuaru/patent.html (last visited July 21, 2026); Japan Patent Off., Examination Guidelines for Patent and Utility Model in Japan pt. V, ch. 1, §§ 2.4, 3.1.2–3.1.3 (Japanese), https://www.jpo.go.jp/system/laws/rule/guideline/patent/tukujitu_kijun/ht/05_0100.html (last visited July 21, 2026).

A timely PCT international filing can preserve the Japanese route: when Article 30(2) treatment is sought for a PCT application, the international application ordinarily must be filed within one year from the loss-of-novelty event. 2024 JPO Applicant Guide, supra, at 15; 2024 JPO Q&A, supra, at 18–19; 2020 Provisional English Guidelines, supra, at 15. The national-phase procedural steps come later, but they do not extend the substantive deadline for the international filing.

The cross-border instruction is therefore asymmetric. A U.S. provisional filed within one year of a disclosure may provide the effective filing date used by U.S. claims, even if a later U.S. nonprovisional follows within the priority year. That provisional does not, by itself, satisfy Japan’s Article 30 filing requirement. If Japan matters, file in Japan or file a PCT application designating Japan before the disclosure anniversary.

VI.            Gate Four: How Much Subject Matter—and How Much Protection Against Third Parties?

A.                 The U.S. inventor-originated exception is disclosure-specific

Section 102(b)(1)(A) removes the inventor-originated disclosure; it does not grant a free-standing one-year immunity from all prior art. If the inventor’s paper disclosed A but a later public demonstration disclosed A+B, each event and its subject matter must be analyzed. And if an independent third party discloses C, inventor origin does not remove C.

Section 102(b)(1)(B) supplies a limited shield against an intervening § 102(a)(1) disclosure only if the intervening disclosure itself was made one year or less before the claimed invention’s effective filing date and, before that disclosure, the inventor—or a person who obtained the subject matter from an inventor—had publicly disclosed the subject matter. 35 U.S.C. § 102(b)(1)(B); MPEP, supra, § 2153.02. The words “publicly disclosed” and “subject matter” do substantial work. A private commercial sale may constitute an inventor-originated § 102(a)(1) event removed by subsection (A), yet fail to establish the public disclosure required by subsection (B). A merely confidential technical communication ordinarily does not become § 102(a)(1) prior art in the first place. See 35 U.S.C. § 102(a)(1), (b)(1)(A)–(B); Sanho Corp. v. Kaijet Technology International Ltd., Inc., 108 F.4th 1376, 1380–85 (Fed. Cir. 2024) (construing § 102(b)(2)(B)’s parallel language and holding that the nonconfidential but otherwise private sale at issue, absent publicization of the relevant subject matter, did not satisfy that provision’s “publicly disclosed” requirement).

The inventor’s earlier public disclosure need not itself fall within that one-year interval as a condition of § 102(b)(1)(B). But if it occurred more than one year before the claimed invention’s effective filing date, it ordinarily becomes unexcepted § 102(a)(1) prior art in its own right. See 35 U.S.C. § 102(a)(1), (b)(1); MPEP, supra, § 2153.02.

Once the timing condition is satisfied, the USPTO interprets “the subject matter disclosed” narrowly. Under current examination guidance, trivial or obvious variations are not automatically the same subject matter; only matching content is removed from the intervening reference. An inventor’s disclosure of a species can protect against a later generic genus disclosure, while disclosure of a genus does not necessarily protect against a later species. MPEP, supra, § 2153.02. This is examination guidance rather than a substitute for controlling precedent, but it is the working rule practitioners must plan around.

Earlier-filed U.S. patent documents require a related analysis. Section 102(a)(2) can treat a U.S. patent, U.S. published application, or qualifying WIPO publication naming another inventor as prior art as of an earlier effective filing date. 35 U.S.C. §§ 102(a)(2), (d). Two relevant exceptions remain within scope here. A patent-document disclosure is removed if its subject matter was obtained directly or indirectly from an inventor. Id. § 102(b)(2)(A). It can also be removed if, before that subject matter was effectively filed, the inventor or an originating source had publicly disclosed the same subject matter. Id. § 102(b)(2)(B).

The second route is not a reason to publish defensively without a filing plan. Although § 102(b)(2)(B) speaks to the sequence between the inventor’s public disclosure and the other patent document’s effective filing date, the inventor’s own public disclosure must still be neutralized under § 102(b)(1) if it precedes the claimed invention’s effective filing date. A public disclosure more than one year before that effective filing date can defeat the applicant even if it came first.

B.                 Japan’s exception neutralizes qualifying events, not independent priority contests

Article 30 treats the qualifying disclosure as not falling under Article 29(1) for applying Article 29(1) and (2). Patent Act art. 30, paras. 1–2. It does not convert the disclosure date into a filing date, create priority over a third party, or neutralize an independently created third-party disclosure simply because it appears during the year. JPO guidance warns that even when Article 30 applies, an earlier third-party filing or publication may prevent a patent. 2024 JPO Applicant Guide, supra, at 1–2; 2024 JPO Q&A, supra, at 17; 2020 Provisional English Guidelines, supra, at 1–2.

Nor does Article 30 cure every patent-document problem. Article 29-2 can apply to subject matter in an earlier-filed, later-published Japanese patent or utility-model application, subject to that provision’s own conditions, and Article 39 separately implements first-to-file rules. Patent Act arts. 29-2, 39. Article 30’s express operation on Article 29(1) and (2) does not displace those provisions.

Japan also demands event-level care for a disclosure series. In principle, a conference abstract, the oral presentation, a trade-show demonstration, and a later website posting can require separate identification and proof. The JPO recognizes limited circumstances in which a later disclosure is so closely related to a proved earlier disclosure that separate treatment can be unnecessary—for example, some faithful reports or downstream posts causally tied to the first act. But an independent publication, a later presentation, or new technical matter should not be assumed covered. 2024 JPO Applicant Guide, supra, at 13–14; 2024 JPO Q&A, supra, at 14–17; 2020 Provisional English Guidelines, supra, at 13–14.

The translation is simple but consequential: the U.S. system has narrow statutory shields for certain intervening disclosures of previously publicized subject matter; Japan’s Article 30 generally does not. In either country, the safest race is still to the patent office, not to the podium.

VII.         Gate Five: What Must Be Filed or Proved?

A.                 United States: no universal filing-time election, but evidence still decides the issue

U.S. practice does not impose the front-loaded statement-and-proof procedure that ordinarily applies to a Japanese national application proceeding under Article 30(2). An application specification may include a statement identifying a prior inventor-originated disclosure, but there is no universal grace-period election at filing. See 37 C.F.R. § 1.77(b)(6) (2026).

When an examiner relies on a disclosure, the applicant may submit an affidavit or declaration under 37 C.F.R. § 1.130. A declaration of attribution can establish that the disclosure was made by an inventor or that the subject matter was obtained from an inventor. A declaration of prior public disclosure can identify the previously disclosed subject matter and date; it must attach the printed publication or, for another mode of disclosure, describe the publicly disclosed subject matter with enough detail to determine what was public on that date. Id. § 1.130(a)–(b); MPEP, supra, §§ 2155.01–.03.

The absence of a short filing-time deadline should not be mistaken for a light evidentiary burden. Years later, a declaration is only as good as the underlying record. Preserve the actual slide deck, paper, source-code release, webpage and archive capture, product specimen, offer documents, confidentiality terms, audience and attendance information, dates, authorship, and transmission chain. For a disclosure by another, document derivation rather than relying on similarity alone.

B.                 Japan: Article 30(2) uses front-loaded procedure, subject to special PCT timing

For an ordinary Japanese national application proceeding under Article 30(2), the applicant must submit a statement seeking the exception at filing and submit a proving document within thirty days after filing. Patent Act art. 30, para. 3. The proof typically identifies the facts of publication—date, place or medium, discloser, and disclosed content—and the facts connecting inventor, right holder, and applicant. 2024 JPO Applicant Guide, supra, at 2–12; 2020 Provisional English Guidelines, supra, at 3–12.

If a proving document cannot be filed within thirty days for reasons beyond the submitter’s control, Article 30(4) permits a narrow delayed submission: within fourteen days after the reason ceases, or two months for an overseas resident, but no later than six months after the original period. Patent Act art. 30, para. 4. The text addresses the proving document; it should not be treated as a cure for omitting the filing-time statement or missing the one-year application deadline.

For a PCT application proceeding under Article 30(2), the Article 30 statement and proving document ordinarily are due within thirty days from the date on which the national-processing standard time occurs. A declaration under PCT Rule 4.17(v) directed to Japan may serve in place of the separate statement, but it does not dispense with the proving document. Patent Act art. 184-14; Regulations Under the Patent Cooperation Treaty rr. 4.17(v), 51bis.1(a)(v); 2024 JPO Applicant Guide, supra, at 15; 2024 JPO Q&A, supra, at 18–19; 2020 Provisional English Guidelines, supra, at 15. The JPO defines the national-processing standard time as expiration of the period for submitting national documents—or, if examination is requested during that period, the time of the examination request. 2024 JPO Applicant Guide, supra, at 15. Calendar this as its own national-phase task.

The Article 30(1) contrary-to-intention route is procedurally different. The applicant need not file the Article 30(2) statement or proving document at filing; evidence can be supplied later, including in response to an examiner. 2024 JPO Applicant Guide, supra, at 15; 2024 JPO Q&A, supra, at 19; 2020 Provisional English Guidelines, supra, at 16–17. The substantive requirement remains: the application must be filed within one year of the contrary-to-intention disclosure.

A procedural option is easy to miss. The provisional English guidelines additionally state that, if the right holder learns before filing that the invention was published contrary to its intention, the applicant may seek Article 30(2) treatment by completing that route’s statement-and-proof procedures. 2020 Provisional English Guidelines, supra, at 16 n.3. The August 2024 Q&A separately confirms that an applicant relying on Article 30(1) need not submit the Article 30(2) filing-time papers, but should explain and prove the contrary-to-intention circumstances through an opinion or written submission. 2024 JPO Q&A, supra, at 19.

VIII.       Worked Cross-Border Problems

A.                 Conference paper and oral presentation

An inventor’s paper is distributed on March 1, and she presents additional experimental detail on March 3. In the United States, each event may be an inventor-originated § 102(a)(1) disclosure removed by § 102(b)(1)(A) if the relevant claims have an effective filing date no later than the following March 1 or March 3, respectively. The comparison is subject-matter-specific.

In Japan, both can potentially qualify under Article 30(2), but counsel should identify both acts and what each made public. The JPO specifically cautions that proving an earlier conference summary does not, in principle, eliminate the need to address the later presentation. 2024 JPO Applicant Guide, supra, at 13–14; 2024 JPO Q&A, supra, at 14–15; 2020 Provisional English Guidelines, supra, at 13–14. File the Japanese or PCT application before the earliest applicable anniversary. For an ordinary Japanese application, submit the Article 30(2) statement at filing and prove each relevant event within thirty days; for a PCT application, follow Article 184-14’s national-phase timing and consider a Rule 4.17(v) declaration.

B.                 U.S. provisional followed by a late Japanese filing

The startup discloses A on January 15, files a U.S. provisional covering A on May 1, and files U.S. and Japanese applications the next May 1. A fully supported U.S. claim to A may use the first May 1 effective filing date, placing the disclosure inside § 102(b)(1)’s year. A Japanese application filed the second May 1 is more than one year after January 15; its U.S. priority claim does not satisfy Article 30. 35 U.S.C. §§ 100(i), 102(b)(1); 2024 JPO Applicant Guide, supra, at 15; 2024 JPO Q&A, supra, at 19; 2020 Provisional English Guidelines, supra, at 14. Any valid priority effect in ordinary Article 29 examination is a separate question; it does not cure the missed Article 30 filing deadline.

C.                 Inventor blog followed by an independent competitor paper

The inventor publicly posts A, and an independent competitor later publishes A+C within the one-year interval before the claimed invention’s effective filing date. In the United States, § 102(b)(1)(B) can remove the intervening reference only as to subject matter previously publicly disclosed by the inventor. C remains available if it was not in the inventor’s post, and USPTO guidance will not extend the exception merely because C is an obvious variation. 35 U.S.C. § 102(b)(1)(B); MPEP, supra, § 2153.02.

In Japan, Article 30 can neutralize the inventor-originated post if its requirements are met. It does not ordinarily neutralize the competitor’s independent paper. Subject to any valid priority claim, that paper may defeat novelty or inventive step under Article 29. Patent Act arts. 29–30; Japan Patent Off., Patent, FAQ 6-8, https://www.jpo.go.jp/e/faq/yokuaru/patent.html (last visited July 21, 2026).

D.                 Confidential recipient leaks the invention

An employee sends A under an NDA to a prospective manufacturer, which posts the drawings. In the United States, the public post may be removed if the applicant proves that the poster obtained A directly or indirectly from an inventor and the post falls within one year of the claim’s effective filing date. 35 U.S.C. § 102(b)(1)(A); 37 C.F.R. § 1.130(a).

In Japan, the leak can fit the Article 30(1) contrary-to-intention route. That route does not require the Article 30(2) filing-time statement or proving document, but the Japanese or PCT application still must be filed within one year, and the applicant should preserve the NDA, transmission record, leaked material, and evidence of the breach. Patent Act art. 30, para. 1; 2024 JPO Applicant Guide, supra, at 15; 2024 JPO Q&A, supra, at 19; 2020 Provisional English Guidelines, supra, at 16–17.

E.                  Private commercial sale

The inventor privately sells a product embodying A under a transaction that does not publicize its technical details. U.S. law may treat the sale as an on-sale event, but an inventor’s private or public sale during the year can be removed under § 102(b)(1)(A). 35 U.S.C. § 102(b)(1)(A); Sanho, 108 F.4th at 1380–82. The particular nonconfidential sale in Sanho did not establish the required public disclosure because neither the sale nor the pertinent product features had been sufficiently publicized. Id. at 1384–85.

In Japan, first determine whether the transaction made A publicly known or publicly worked within Article 29(1). The absence of a public technical explanation is relevant but not dispositive; the inquiry turns on what the transaction, the product, or its resulting use made available to unspecified persons without an obligation of secrecy. If the transaction did not bring A within Article 29(1), Article 30 may not be needed; if it did, Article 30(2) may be available with timely filing and procedure. Patent Act arts. 29, para. 1, 30, para. 2; 2024 JPO Applicant Guide, supra, at 8–9; 2024 JPO Q&A, supra, at 9, 15–16; 2020 Provisional English Guidelines, supra, at 8 n.1. The same invoice can thus trigger different threshold questions in the two systems.

IX.             Conclusion

The U.S. and Japanese one-year rules are best understood as emergency bridges, not filing strategies. The U.S. bridge is built around the source and subject matter of a disclosure and the effective filing date of each claimed invention. Japan’s bridge is built around a qualifying act or contrary-to-intention disclosure, an actual Japanese or PCT filing within one year, and—when the applicant proceeds under Article 30(2)—the applicable statement-and-proof procedure, including the special PCT timing.

For Japanese counsel translating U.S. law, the decisive shift is from an application-centered exception to a claim-specific effective-filing-date and inventor-origin analysis, with narrow protection against some intervening disclosures. For U.S. counsel translating Japanese law, the decisive shift is from flexible prosecution-stage proof to a filing-centered exception with strict initial procedure and no general shield against independent third parties.

The shared phrase “one-year grace period” should therefore trigger questions, not reassurance. What happened? Who caused it? What exactly became public or went on sale? Which filing date governs in this country? What evidence and forms are due? Once those questions are separated, the two systems become intelligible to each other—and the calendar becomes much harder to misread.