Keeping the Family Open: U.S. Continuation Practice Compared with Europe, China, Korea, and Japan

Executive Summary: U.S. continuation practice is a uniquely powerful portfolio-management tool because it allows applicants to keep a patent family pending and pursue additional same-disclosure claim sets as markets, competitors, prior art, licensing needs, and litigation positions evolve. By contrast, Europe, China, Korea, and Japan offer important but more constrained follow-on mechanisms—principally divisionals, Korea’s narrower split/separate application procedure, and post-grant limitation or correction tools—that may preserve or narrow rights but generally do not replicate the routine claim-development flexibility of a U.S. continuation. The practical lesson for global patent strategy is that U.S. continuations should be used deliberately when a real claim objective justifies the added cost, while foreign prosecution requires early, jurisdiction-specific planning around divisional windows, original-disclosure limits, claim-count economics, grant or appeal deadlines, and post-grant correction constraints.

I.             Introduction

U.S. continuation practice is one of the most important strategic differences between U.S. patent prosecution and patent prosecution in Europe, China, Korea, and Japan. In the United States, a patent family can often be kept pending through a same-disclosure continuation, allowing the applicant to pursue additional claim sets directed to subject matter already disclosed in the parent application. That ability makes U.S. continuation practice not merely a procedural device, but a portfolio-management tool.

The comparison with foreign practice is often misunderstood. Foreign associates and clients may use terms such as “continuation,” “divisional,” “child application,” or “follow-on application” interchangeably, but the legal mechanisms are not interchangeable. Europe, China, Korea, and Japan do provide mechanisms that may preserve additional claim opportunities based on an earlier disclosure, but those mechanisms are typically divisional, split/separate-application, or post-grant correction mechanisms subject to jurisdiction-specific constraints. The better comparative point is not that foreign systems lack strategic value; it is that they generally do not provide the same routine, same-disclosure, claim-development flexibility that U.S. continuation practice provides.

The central distinction is this: U.S. continuation practice allows iterative claim development within the four corners of the original disclosure; foreign practice may preserve some same-disclosure claim opportunities, but generally through more constrained mechanisms governed by timing, added-matter, unity, pendency, fee, and procedural limits.

II.         The U.S. continuation as the workhorse

A U.S. continuation application is a later application directed to subject matter disclosed in a prior copending application and filed in a manner that preserves the benefit of the earlier filing date, provided the requirements of 35 U.S.C. § 120 and 37 C.F.R. § 1.78 are met. The USPTO describes a continuation as an application for inventions disclosed in a prior-filed copending application, where the continuation disclosure must not include subject matter that would constitute new matter if added to the parent by amendment. MPEP § 201.07; 35 U.S.C. § 120; 37 C.F.R. § 1.78(d).

The ordinary U.S. continuation is a same-disclosure application. It allows the applicant to pursue a different claim set—broader, narrower, differently focused, directed to a different statutory class, or directed to a different commercial embodiment—so long as the claims are supported by the disclosure and satisfy the other requirements of patentability. The USPTO guidance recognizes that a continuation may be filed before patenting, abandonment, or termination of proceedings in the earlier application to introduce a new set of claims and obtain further examination. MPEP § 201.07; 37 C.F.R. § 1.53(b).

This is different from a U.S. divisional. A divisional is generally used to pursue subject matter carved out from the parent application, often after a restriction requirement. Divisional status may matter for 35 U.S.C. § 121 safe-harbor purposes and for obviousness-type double patenting analysis. Continuations and divisionals are both continuing applications, but they are not synonyms. See 35 U.S.C. §§ 120–121; MPEP §§ 201.06, 201.07.

Continuation-in-part applications should not be overemphasized. A CIP is legally available in the United States, but it is not the ordinary U.S. continuation strategy. The USPTO describes a CIP as an application filed during the lifetime of a prior-filed application that repeats some or all of the earlier disclosure and adds matter not disclosed in the earlier application. MPEP § 201.08.

Although CIPs are part of the statutory vocabulary of U.S. continuing-application practice, empirical work supports treating them as secondary to the same-disclosure continuation. Righi, Cannito, and Vladasel describe continuations as the most widespread type of continuing application and distinguish them from CIPs, which add new matter; in one of their main samples, the mean incidence of continuation filings was 9.87%, compared with 3.36% for CIPs. See Cesare Righi, Davide Cannito & Theodor Vladasel, Continuing Patent Applications at the USPTO, 52 Research Policy art. 104742 (2023); see also Cesare Righi, Davide Cannito & Theodor Vladasel, Continuing Patent Applications at the USPTO 6, 37 tbl.5 (Barcelona Sch. of Econ. Working Paper No. 1382, Jan. 2023). The better practical characterization is therefore that the same-disclosure continuation—not the CIP—is the ordinary U.S. continuation tool, while the CIP is a less common, special-purpose filing used when new matter must be added.

The CIP also creates priority complexity. Claims supported by the parent may be entitled to the parent’s filing date; claims relying on added matter are not. For that reason, a CIP should generally be treated as a special-purpose filing used only when new disclosure is needed and when the applicant has considered whether a new application would be cleaner. MPEP § 201.08; 35 U.S.C. § 120.

III.      Why keeping U.S. prosecution open creates value

The most important commercial feature of U.S. continuation practice is that it preserves claim optionality. A first application is often filed before the applicant knows which embodiments will matter most, which competitors will enter the market, which product architecture will prevail, or which prior art will shape the eventual claim scope. A pending continuation allows the applicant to use later-acquired business and technical information to pursue claims supported by the original disclosure. MPEP § 201.07.

That optionality has direct portfolio value. Patent value is claim value. A specification may describe a broad technical platform, but the exclusionary right is defined by the claims. See 35 U.S.C. § 154(a)(1). A continuation allows the applicant to convert disclosed but unclaimed or underclaimed subject matter into targeted claims that map to products, services, system architectures, customer workflows, manufacturing steps, or design-arounds.

A continuation also allows claims to follow the market. The applicant’s commercial product may change. A competitor may adopt a different implementation. A standard may evolve. A potential licensee may identify different features as commercially important. A continuation allows prosecution strategy to mature with that information, provided the resulting claims remain adequately supported by the original disclosure. MPEP § 201.07; 35 U.S.C. § 112(a).

For operating companies, this can make a U.S. family more valuable in licensing, cross-licensing, investment, and M&A. A pending continuation is a strategic option: the owner or acquirer may still shape future claim coverage within the existing disclosure. That optionality can have independent value even before the continuation issues, particularly where the issued claims cover one product generation but the pending claims can be directed to later versions or adjacent commercial embodiments. See 35 U.S.C. § 120; MPEP § 201.07.

IV.      The litigation value of open U.S. prosecution

Open prosecution is especially important in U.S. litigation because U.S. courts construe claims; they do not generally rewrite or amend them. The Federal Circuit’s statement in Chef America remains a useful warning: courts may not redraft claims “whether to make them operable or to sustain their validity.” Chef Am., Inc. v. Lamb-Weston, Inc., 358 F.3d 1371, 1374 (Fed. Cir. 2004).

That matters because litigation often exposes claim defects or claim gaps. A defendant’s non-infringement position may reveal that a claim term is narrower than the patentee expected. Claim construction may remove a product from the literal scope of the asserted claims. Invalidity contentions may identify prior art that leaves narrower, commercially meaningful claim space. Technical discovery may reveal a different implementation than the patentee initially assumed. A continuation does not fix the asserted claims in the pending case, but it can provide a separate prosecution track for new claims informed by the litigation record. MPEP § 201.07.

The same point applies to IPR, ex parte reexamination, and parallel district court litigation. An IPR is limited to §§ 102 and 103 grounds based on patents and printed publications. 35 U.S.C. § 311(b). Ex parte reexamination requires a substantial new question of patentability based on prior patents or printed publications. 35 U.S.C. §§ 302–304; 37 C.F.R. § 1.510(b)(1); MPEP § 2216. District court litigation may surface those references, but also product prior art, system prior art, on-sale or public-use evidence, § 112 arguments, claim-construction positions, and technical facts about the accused product.

If a continuation remains pending, the patent owner can submit material information to the USPTO and pursue claims that are patentably distinct over the newly surfaced art. The duty of disclosure is central to this strategy. Each individual associated with filing and prosecution has a duty of candor and good faith, including a duty to disclose known information material to patentability, and that duty exists for each pending claim until the claim is cancelled, withdrawn, or the application becomes abandoned. 37 C.F.R. § 1.56(a); MPEP § 2001.

Litigation-informed claim drafting is not improper merely because it is commercially targeted. The Federal Circuit recognized in Kingsdown that there is nothing inherently wrong with amending or inserting claims to cover a competitor’s product learned about during prosecution, so long as the claims and prosecution conduct comply with the patent laws and rules. Kingsdown Med. Consultants, Ltd. v. Hollister Inc., 863 F.2d 867, 874 (Fed. Cir. 1988) (en banc).

The litigation value of open prosecution should not be overstated. A continuation cannot add new matter. It may not issue in time to affect a pending case. It may face written-description, enablement, definiteness, prior-art, obviousness-type double-patenting, terminal-disclaimer, estoppel, prosecution-history, or prosecution-laches issues. The doctrine of double patenting, for example, is intended to prevent unjustified extension of patent exclusivity beyond the patent term. MPEP § 804.

Still, a pending continuation can materially affect settlement and licensing leverage. An accused infringer may defeat or design around one issued claim set, but a pending continuation can preserve the possibility of later-issued claims that are better aligned with the accused technology and examined over the art developed in the dispute. That makes open prosecution a litigation asset, not merely a prosecution convenience.

V.          Cost: open prosecution is valuable, but not free

A continuation should be treated as a budgeted claim option. It requires a new filing, new official fees, attorney time, IDS review, claim drafting, prosecution, possible RCE or appeal costs, and, if allowed, a separate issue-fee and maintenance-fee stream. USPTO fee guidance makes clear that nonprovisional applications involve filing, search, and examination fees, and current USPTO maintenance fees are due at 3.5, 7.5, and 11.5 years for each issued utility patent. 35 U.S.C. § 41(b); 37 C.F.R. §§ 1.16, 1.20.

Long continuation chains now face additional official-fee pressure. The USPTO fee schedule includes large-entity fees for presenting a benefit claim more than six years after the earliest benefit date and more than nine years after the earliest benefit date. 37 C.F.R. § 1.17(w); USPTO Fee Schedule.

Continuations also usually preserve claim flexibility, not patent term. For continuation, divisional, and CIP applications filed on or after June 8, 1995, the patent term generally ends twenty years from the filing date of the earliest application for which benefit is claimed under 35 U.S.C. §§ 120, 121, 365(c), or 386(c). 35 U.S.C. § 154(a)(2); MPEP § 2701.

The practical rule should be simple: do not file a continuation merely because the parent is allowed. File it because there is a claim set worth preserving. The continuation decision should answer four questions: What claim set do we want that we do not already have? What product, competitor, standard, licensee, design-around, or fallback position does it support? Is it supported by the existing disclosure? Does the expected commercial value justify the filing, prosecution, and maintenance costs?

VI.      Europe: divisional practice, central limitation, and national or UPC claim limitation

European practice is centered on divisional applications, not U.S.-style continuations. Article 76(1) EPC provides that a European divisional application may be filed only for subject matter that does not extend beyond the content of the earlier application as filed; if that requirement is met, the divisional is deemed filed on the filing date of the earlier application and enjoys any priority right. Convention on the Grant of European Patents art. 76(1) [hereinafter EPC]. Rule 36(1) EPC provides that the applicant may file a divisional application relating to any pending earlier European patent application. EPC r. 36(1).

The resulting comparison with U.S. practice is nuanced. Europe has no U.S.-style continuation application, but European divisionals may provide some same-disclosure claim-preservation functionality if filed while the parent remains pending and if the divisional survives the EPC’s strict added-matter, pendency, fee, and prosecution constraints. That makes the European divisional strategically important, but it is still not equivalent to the ordinary U.S. same-disclosure continuation.

Pendency is a central limitation. EPO guidance states that the parent application must be pending when the divisional is filed; an application is pending up to, but not on, the date the European Patent Bulletin mentions grant. The same guidance states that a refused application remains pending for Rule 36(1) purposes until expiration of the time limit for filing the notice of appeal if no appeal has yet been filed, and that divisionals cannot be validly filed once the parent application has been finally refused, withdrawn, or deemed withdrawn, subject to specific remedial situations. EPO Guidelines for Examination, A-IV, 1.1.1.

European post-grant practice also differs from U.S. litigation practice. Article 138(3) EPC provides that, in proceedings before a competent court or authority relating to validity of a European patent, the proprietor has the right to limit the patent by amending the claims, and the patent as limited forms the basis for the proceedings. EPC art. 138(3). The UPC Agreement likewise provides that, if the grounds for revocation affect the patent only in part, the patent is limited by a corresponding amendment of the claims and revoked in part. Agreement on a Unified Patent Court art. 65(3).

European law also provides a central EPO limitation procedure. Article 105a EPC allows the proprietor to request that a European patent be revoked or limited by amendment of the claims, with the request filed at the EPO and deemed filed only after payment of the limitation or revocation fee. But Article 105a(2) bars the request while opposition proceedings concerning the European patent are pending. EPC art. 105a.

These European limitation mechanisms are consistent with the same basic distinction. Article 138(3), UPC Article 65(3), and Article 105a EPC provide narrowing or defensive limitation mechanisms; they do not provide a U.S.-style continuation vehicle for prosecuting a new claim set as market, litigation, or prior-art information develops. A European patentee may have meaningful tools to preserve validity by narrowing claims, but those tools are not a substitute for keeping a U.S. continuation family pending.

Cost is also a major European constraint. Rule 36(3) EPC requires the divisional filing and search fees to be paid within one month of filing, and EPO guidance states that the search fee must be paid even if a further search fee was already paid on the parent for lack-of-unity subject matter now pursued in the divisional. EPC r. 36(3); EPO Guidelines for Examination, A-IV, 1.4.1. Renewal fees for a divisional are calculated from the parent or root filing date, and renewal fees already fallen due for the parent may fall due for the divisional upon filing, creating a catch-up cost. EPO Guidelines for Examination, A-IV, 1.4.3.

For U.S. applicants, the European takeaway is: make the divisional decision before grant, refusal finality, withdrawal, or deemed withdrawal forecloses the option. If commercially meaningful subject matter remains unclaimed in the EP application, counsel should assess whether a divisional is worth the filing, search, examination, claim-fee, renewal catch-up, validation, and unitary-patent costs.

VII.   China: divisional timing tied to the Rule 60 grant-formality deadline and narrow invalidation amendment

China likewise does not provide a U.S.-style continuation system. Chinese practice is based on divisional applications, and the timing rule is precise. The current Implementing Regulations, as translated by AFD China Intellectual Property, provide that where a patent application contains two or more inventions, utility models, or designs, the applicant may file a divisional application before expiration of the time limit provided in Rule 60(1). Implementing Regulations of the Patent Law of the People’s Republic of China r. 48. Rule 60(1), in turn, provides that after CNIPA issues a notification to grant the patent, the applicant must complete registration formalities within two months from receipt of the notification. Implementing Regulations r. 60(1).

For U.S. readers, the practical shorthand is that a voluntary Chinese divisional generally must be considered before grant formalities are completed and before the Rule 60 registration-formality period expires. But the precise legal hook matters: the timing is tied to the Rule 60(1) registration-formality deadline, not to an open-ended U.S.-style pendency concept. Rule 48 also provides that no divisional may be filed where the application has been rejected, withdrawn, or deemed withdrawn, and the divisional may not change the type of the initial application. Implementing Regulations r. 48.

Rule 49 supplies the priority and disclosure constraint. A divisional filed under Rule 48 is entitled to the filing date, and any claimed priority date, of the initial application only if it does not go beyond the scope of disclosure contained in the initial application. Implementing Regulations r. 49. This makes Chinese divisional practice potentially useful for preserving disclosed subject matter, but it is not a continuation-like mechanism for later claim development divorced from the original disclosure and the Rule 48/Rule 60 timing framework.

Post-grant, China is also not a continuation-like system. Validity is handled through CNIPA invalidation proceedings. After grant, any entity or individual may request invalidation, and CNIPA examines the request and issues a decision; a dissatisfied party may bring suit in a people’s court within three months from receipt of the decision. Patent Law of the People’s Republic of China arts. 45–46.

China permits amendment during invalidation, but the mechanism is narrow. Rule 73 provides that, during examination of an invalidation request, the patentee of an invention or utility model patent may amend the claims but may not broaden the scope of patent protection. The patentee may not amend the description or drawings for an invention or utility model patent, and a design patentee may not amend the drawings, photographs, or brief specification. Implementing Regulations r. 73.

For litigation strategy, this means that a Chinese patentee generally cannot recreate the U.S. continuation strategy after grant. If litigation or invalidation reveals new prior art, the patentee’s response is typically defensive claim amendment in CNIPA invalidation, not prosecution of a fresh claim set in a still-pending continuation. If a Chinese divisional remains available, it must satisfy the Rule 48 timing requirements, the Rule 49 original-disclosure requirement, and the prohibition on changing application type.

Chinese costs are different from U.S. and European costs, but they are not negligible. CNIPA’s fee schedule lists, among other fees, an invention filing fee of CNY 900, an invention substantive examination fee of CNY 2,500, additional claim fees for each claim exceeding ten, annual fees, and invalidation-request fees. CNIPA Patent Fee Schedule. Foreign applicants should also budget for Chinese translation, local counsel, office-action responses, divisional prosecution, and annuity management.

The Chinese takeaway is: decide early and docket the grant-formality period carefully. Because the divisional route is tied to Rule 48, Rule 60, parent status, application type, and original disclosure, U.S.-style “keep it pending and decide later” thinking can easily miss the Chinese opportunity.

VIII.                 Korea: divisionals, separate/split applications, and IPTAB correction

Korea is likewise a non-U.S.-continuation jurisdiction, but its practice requires more nuance than a simple divisional-only characterization. Korean divisional practice is governed by Article 52 of the Korean Patent Act, which permits an applicant who has filed a single patent application for two or more inventions to divide the application into two or more applications within the scope of the features described in the specification or drawings accompanying the initial application and within specified prosecution windows. Korean Patent Act art. 52(1) (S. Kor.). A Korean divisional is generally deemed filed at the time the initial patent application was filed, subject to statutory exceptions. Id. art. 52(2).

Korean divisionals can provide some continuation-like strategic flexibility, particularly where the original disclosure supports additional claims and the applicable filing window remains open. But the mechanism remains a divisional, not a U.S.-style same-disclosure continuation. It depends on the original disclosure, Korean timing rules, and Korean double-patenting and same-invention principles.

Korean practice also includes a post-2022 split/separate application mechanism. The official English translation of the Korean Patent Act refers to this mechanism as “splitting-off.” Article 52-2 provides that a person who has received a decision to reject a patent application may split off part of the application into a new patent application, within the scope of the features described in the specification or drawings accompanying the initial application, within 30 days from receipt of the certified copy of the trial ruling if a petition for trial under Article 132-17 is dismissed. Korean Patent Act art. 52-2(1) (S. Kor.). The statute limits the claims that may be pursued, including claims not rejected in the decision to reject the application and certain limited claim forms derived from rejected or originally described subject matter. Id. art. 52-2(1)(1)–(4).

This split/separate application mechanism is narrower than U.S. continuation practice. Article 52-2 is tied to a specific procedural posture: dismissal of an appeal from a final rejection. It is also constrained by downstream-application limits. Article 52-2(4) provides that a splitting-off “shall not form the basis of a new splitting-off, a divisional application, or a converted application.” Korean Patent Act art. 52-2(4) (S. Kor.). A Korean-practice commentary by Yunsoon Choi of Yoon & Yang similarly explains that the separate application system took effect on April 20, 2022, may be used after dismissal of an appeal from a final rejection, must be filed within 30 days from service of the dismissal decision, is limited to claims not rejected in the final rejection, and cannot serve as the basis for an additional separate, divisional, or converted application. Yunsoon Choi, Introduction of a Separate Application System: Revision of Korean Patent Law, APAA e-Newsletter, Issue No. 27 (Feb. 2022).

This mechanism preserves the broader distinction while adding an important Korean-specific nuance. Korea is not a U.S.-style continuation jurisdiction, but Korean practice does include a targeted claim-preservation mechanism beyond ordinary divisionals. The split/separate application is best characterized as a narrow safety valve for preserving certain unrejected subject matter after an unsuccessful appeal, not as an open-ended vehicle for market- or litigation-informed claim development.

Post-grant, Korea provides correction mechanisms through the Korean Intellectual Property Trial and Appeal Board. Article 136 permits a trial for correction where the patentee seeks to reduce the number of claims, rectify a clerical error, or clarify an ambiguous description. Korean Patent Act art. 136(1) (S. Kor.). Correction is subject to substantive limits: it must remain within the specification or drawings of the patented invention, must not substantially extend or amend the claims, and certain corrected claims must remain patentable. Id. art. 136(3)–(5). When a correction ruling becomes final and conclusive, the application, grant decision or trial ruling, and registration are deemed to have been made according to the corrected specification or drawings. Id. art. 136(10).

Korean infringement courts may consider validity-type defenses, including abuse-of-rights arguments, but formal correction remains tied to tribunal practice rather than a U.S.-style judicial rewriting of the claims or a continuation-like prosecution path.

Cost is a particularly important Korean issue because claim count directly affects official fees. KIPO’s current fee schedule lists an electronic patent application fee of KRW 46,000 and a substantive examination fee consisting of a KRW 166,000 basic fee plus KRW 51,000 for each patent claim. KIPO, Fees and Payments (Patent Fees). Annual fees also include both basic and per-claim components. Id.

The Korean takeaway is: use divisionals and split/separate applications deliberately and control claim count. A Korean divisional can preserve an additional claim family, and a split/separate application can preserve certain unrejected subject matter after appeal dismissal, but neither mechanism should be treated as equivalent to a U.S. continuation. Each should be justified by a distinct commercial objective and budgeted in light of per-claim examination and annuity costs.

IX.      Japan: divisional windows, correction trials, and early coordination of claims and examination

Japan, like Korea and China, does not provide broad U.S.-style continuation practice. Japanese Patent Act Article 44 permits an applicant to divide a patent application containing two or more inventions into one or more new patent applications only within specified procedural windows, including periods when amendments are allowed, within 30 days from service of a grant decision, and within three months from service of an examiner’s initial rejection decision. Patent Act art. 44(1), Act No. 121 of 1959 (Japan). A lawful divisional is generally deemed filed at the time of filing of the original application. Patent Act art. 44(2) (Japan).

The “two or more inventions” formulation is important. Japanese divisional practice is therefore more specific than a generic “child case” concept. Because Article 44 refers to division of an application containing two or more inventions and because the filing windows are tied to amendment periods and short post-decision periods, Japanese divisional strategy should be coordinated early with original claim drafting, deferred examination, office-action strategy, and commercial claim planning. Patent Act art. 44(1) (Japan).

Japan also differs from the United States in litigation and post-grant correction. Article 104-3 provides that, in infringement litigation, if the patent is recognized as one that should be invalidated by a trial for patent invalidation, the patentee’s rights may not be exercised against the adverse party. Patent Act art. 104-3(1) (Japan). That is a validity defense in litigation; it is not a court-administered continuation mechanism.

Formal correction occurs through JPO procedures. Article 126 allows a trial for correction, limited to purposes such as restricting the claims, correcting errors or mistranslations, clarifying ambiguous statements, and rewriting dependent claims in independent form. Patent Act art. 126(1) (Japan). Article 134-2 permits correction requests during invalidation trials, subject to specified timing and purpose limits. Patent Act art. 134-2(1) (Japan).

Japan therefore provides meaningful defensive correction practice, but it does not provide the same litigation-informed open prosecution that a pending U.S. continuation provides. If prior art or technical facts emerge in litigation, a Japanese patentee may be able to defend by correction, but that correction is a controlled narrowing mechanism. It is not a vehicle for prosecuting new claims in the same way that a U.S. continuation can be.

Japanese cost planning should focus heavily on examination and claim count. JPO’s fee schedule lists a patent application fee of ¥14,000 and, for patent applications filed on or after April 1, 2019, a request-for-examination fee of ¥138,000 plus ¥4,000 per claim. Annual patent fees also include per-claim components that increase by patent-year bands. JPO Fee Schedule.

The Japanese takeaway is: use the divisional windows and deferred examination structure strategically, but do not assume that a Japanese application can be kept open like a U.S. continuation family. Because Article 44 is tied to applications containing two or more inventions and to specific procedural windows, the original claim set, examination-request timing, office-action responses, and divisional planning should be coordinated before the statutory windows close.

X.          Conclusion

The core difference between U.S. continuation practice and EP, Chinese, Korean, and Japanese practice is not merely terminology. The U.S. continuation is a strategic claim-development mechanism. It allows a patent owner to keep prosecution open and pursue claims that reflect later market information, competitor activity, licensing needs, prior art, and litigation developments. That flexibility can materially increase the value of a U.S. patent portfolio.

Europe, China, Korea, and Japan provide important tools, but they are different tools. Europe provides divisionals that can preserve same-disclosure claim opportunities if filed while the parent remains pending and if the application satisfies strict added-matter, pendency, fee, and prosecution constraints; Europe also provides central limitation under Article 105a EPC and claim limitation in national or UPC validity proceedings. China provides divisionals tied to Rule 48 and the Rule 60 grant-formality deadline, along with narrow claim amendment in CNIPA invalidation. Korea provides divisionals, a narrower post-2022 separate/split application mechanism for certain unrejected claims after appeal dismissal, and IPTAB correction. Japan provides divisionals under Article 44’s “two or more inventions” framework and JPO correction trials or correction requests in invalidation.

The practical lesson for U.S. patent attorneys is straightforward: keep U.S. prosecution open when there is a real claim objective, but do not assume the same strategy can be exported. For global portfolios, the best practice is to draft broadly and precisely at the outset, docket foreign divisional and split/separate-application windows independently, budget continuation and foreign follow-on costs realistically, and use U.S. continuations as deliberate claim options rather than reflexive filings.