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In the previous article, we analyzed the core “Splatoon” patent (Patent No. 5980266) based on its...
Learning "Divisional Application" Strategies from Game Companies: Practical Insights from the Splatoon Patent Portfolio and the Palworld Litigation [Explanation by a
In this blog series, we’ve been analyzing Nintendo’s game patents at the claim level through our “Splatoon Patent Series” (5 parts) and our breakdown of the Palworld patent litigation. The keyword that runs through the entire series is “divisional applications.”As a summary of the series, this article systematically examines “what a divisional application strategy is, why it works, and how to apply it within your own company” using real-world examples from game companies. This practical guide is intended not only for the gaming industry but also for intellectual property professionals at software companies and startups.
Table of Contents
- What Is a Divisional Application?—Three Basic Rules
- Case Study 1: The Splatoon Patent Portfolio—Slicing the Experience into “Layers”
- Case Study 2: Palworld Litigation—Agile Responses to Later-Launched Products and Their Limitations
- Practical Checklist for Implementing This in Your Company
- A Third-Party Perspective—FTO Extends to “Family Monitoring”
- Summary + Consultation Information
1. What Is a Divisional Application?—Three Basic Rules
A divisional application (Patent Law Article 44) is a procedure in which a portion of a pending patent application is separated to form a new application. There are three key rules to understand when formulating a strategy.
| Rule | Details |
|---|---|
| ① Retroactive Effect | A valid divisional application is deemed to have been filed on the filing date of the original application, and the reference date for determining novelty and non-obviousness is retroactive to the filing date of the original application. Even in the case of a divisional application of a divisional application (re-division), the reference date is retroactive to the filing date of the original application. |
| ② Limitations on the Scope of Disclosure | Claims filed in a divisional application are limited to the scope disclosed in the original specification and other documents of the parent application (addition of new matters is not permitted). Inventors cannot freely “add” new elements to the invention at a later date. |
| ③ Time Constraints | A divisional application may only be filed at specific statutory time points, such as during the period for amendments, within 30 days after service of the notice of grant, or within three months after service of the first notice of rejection. Keeping the application pending is a prerequisite for preserving the opportunity to file a divisional application. |
Combining these three points reveals the essence of a divisional application. Namely, it is a “mechanism that allows claims based on different perspectives to be formulated later, while maintaining the strong reference date of the filing date.” However, the degree of flexibility depends on: ① how long the application family remains pending, and ② how extensively the disclosure is set forth in the specification of the original application.
2. Case Study 1: The Splatoon Patent Family—Slicing the Experience into “Layers”
The patent family protecting “Splatoon’s” Turf War mode branches out across three generations—parent, child, and grandchild—from a single parent application filed on May 14, 2014 (the bibliographic information for each patent has been verified in the original Google Patents documents; please refer to the respective articles for details).
Patent Application 2014-100714 (Original Filing Date: May 14, 2014)
= Patent No. 5980266
(Parent/Core)
└─ Division (July 25, 2016) Patent Application No. 2016-145245
= Patent No. 6283072
(Child)
├─ Re-division (January 25, 2018) = Patent No
. 6543361
(Grandchild/Older Brother)
└─ Re-division (January 25, 2018) = Patent No. 6561155
(Grandchild/Younger Brother)
It is worth noting that these four patents are not merely variations, but rather represent different “layers” of a single gaming experience.
| Patent | Layer | Focus of the Claims |
|---|---|---|
| 5980266 (Parent) | Game Rules Layer | Filling + Match Determination Based on Drawing State + Differences in Behavior Within the Player’s Color Area |
| 6283072 (Child) | Control System Layer | "Separate inputs" for movement and drawing + attacks + victory/defeat determination based on filled area |
| 6543361 (Grandchild) | Behavior Control Layer | Behavior differs only based on whether the area is the player’s own color or not (excluding match determination from requirements) |
| 6561155 (Sun) | Communication Layer | Generation, transmission, reception, and reproduction of rendering event data (online synchronization) |
Two design approaches can be inferred from this. First, the distinction between “addition” and “subtraction.”Child 6283072 adds the constraints of “separate input” and “attack,” delving into the design philosophy of the control system, while grandchild 6543361, conversely, subtracts “battle determination” to ensure a wide range of operation regardless of whether a battle is taking place.Second, the simultaneous deployment of layers through “same-day splitting.” On January 25, 2018, two separate layers—Behavior Control (6543361) and Communication Synchronization (6561155)—were spun off on the same day.
Practical Tips (Robustness):Broad claims (with few requirements) tend to align closely with prior art and are prone to invalidation risks, while narrow claims (with many requirements) are easily circumvented—in response to this trade-off, splitting the application to run multiple claims in parallel—with varying scopes and perspectives—functions as a “diversified investment in rights,” ensuring that even if some are invalidated, others will survive.
3. Case Study 2: Palworld Litigation—Agile Response to Later-Launched Products and Its Limitations
If the division of the *Splatoon* patents was about “building a patent portfolio for the future,” what was observed in the *Palworld* patent litigation was a more agile approach: “responding via divisional applications after the emergence of a follow-on product.” The timeline, as confirmed from publicly available information, is as follows:
December 22, 2021: Original applications filed
for the three target patents (approximately one month before the release of *Pokémon LEGENDS Arceus*)
January 19, 2024: *Palworld* Early Access released
February–July 2024: Three divisional applications
filed, utilizing expedited
examination May–August 2024: All three registered
(the last patent, No. 7545191, was granted approximately three weeks before the lawsuit was filed)
September 18, 2024: Lawsuit filed with the Tokyo District Court (pending)
In other words, the patents asserted in the lawsuit did not exist at the time the target product was launched; they were granted after the launch through a combination of divisional applications and expedited examination.Since novelty and non-obviousness are determined based on the filing date of the original application in 2021 due to retroactive effect, this is a strategy that is legally permissible under the system (Note: Whether the claims were drafted with the subject product in mind is a third-party analysis and not a fact acknowledged by the parties.Furthermore, the question of whether infringement occurred and the validity of the patent remain undetermined as the case is still pending).
At the same time, this case also highlights the limitations of the divisional application strategy. First, since the assessment is based on the retroactive filing date “standard,” the patent remains vulnerable to prior art predating the original filing date (the defendant has argued for invalidity based on prior art such as ARK, and the Japan Patent Office has issued a notice of rejection for lack of non-obviousness regarding the related divisional applications.(Neither of these is a final decision.) Second, the practical benefit of a future injunction may be diminished due to changes in the opposing party’s specifications (design circumvention). Third, due to the prohibition on adding new matters, configurations not described in the specification of the original application cannot be claimed.
4. Practical Checklist for Your Company
Based on these two cases, the practical steps for rights holders can be summarized in the following checklist. This applies not only to games but also to software, IoT, and manufacturers’ products in general.
□ At Filing: Write a comprehensive specification to serve as a
“reservoir for future divisional applications”
Disclose embodiments, variations, and alternative perspectives (control systems, behavior, communication, UI) even if you do not intend to use them in the claims. The flexibility for filing divisional applications several years later is determined at this stage.
□ Keep the application family for key products “pending” at all times
If you close the family after registration, you lose future opportunities for divisional applications. For core inventions, consider “maintaining the pipeline” by keeping at least one divisional application pending.
□ Build layers through new applications and divisional
applications with each sequel or update
File applications for new features before public disclosure (the new actions in Splatoon 3 were filed three days before the announcement). Reinforce existing application families with divisional applications that shift the focus.
□ Design claim sets with a balance of
“addition” and “subtraction” in mind
Run both narrowly defined claims targeting specific implementations and broadly defined claims covering only core elements in parallel. Ensure consistency across categories (system/program/device/method).
□ Establish Cost-Effectiveness
Thresholds
Filing, examination, and maintenance costs are incurred for each division. Rather than covering all products, establish criteria in advance to focus on “products that are the pillars of the business” and “features with a high risk of imitation.”
5. The Third-Party Perspective—FTO Extends to “Family Monitoring”
Conversely, these strategies pose risks for new entrants and latecomers. The most important lesson from the Palworld lawsuit was that “even if a product clears a search for registered patents at the time of release, you cannot rest easy.” This is because, as long as a competitor’s pending application family remains, divisional claims tailored to your product’s specifications could be filed later.
Key points of FTO (Freedom-to-Operate) searches: ① Include not only registered patents but also published applications and pending divisional families in the scope of the search; ② Regularly monitor the application families of major competitors even after release;③ Since claims are not written using proper nouns, search using combinations of abstract concept keywords, patent classifications, and applicant names; ④ In preparation for the event that risks materialize, consider design-around options and invalidity evidence (including non-patent literature such as prior-art games and videos) in advance.
6. Summary + Consultation
Divisional applications are a dual-purpose system that can be used to “secure rights to a single invention from multiple angles” (the “Splatoon” model) or to “respond flexibly to the emergence of later products” (the model observed in the Palworld litigation).The source of its power lies in retroactive effect, while its limitations lie in the scope of disclosure of the original application and prior art. That is precisely why the thorough preparation of the initial specification and the management of the application family to keep it pending will determine your ability to respond to disputes several years down the line.
In each installment of this series, we provide a detailed explanation of the content summarized here, including direct quotations from the claims.Please also refer to: General Overview / No. 5980266 (Core) / No. 6283072 (Additive Division) / No. 6543361 (Subtractive Division) / No. 6561155 (Communication Layer) / Palworld Patent Litigation
Consultation with Evorix Intellectual Property Law Firm
At Evorix Intellectual Property Law Firm (evorix.jp), we offer consultations on the design of specifications and claims with an eye toward divisional applications, management strategies for patent families, and FTO (Freedom-to-Operate) investigations, including monitoring of competing patent families. Please feel free to contact us via the inquiry form to discuss how to secure intellectual property rights for the core functions of your products.
*This article is intended to provide general information and does not guarantee any specific outcome in individual cases. The patent and litigation information contained herein is based on publicly available information as of the time of writing (July 2026). With regard to pending litigation, this article does not make any definitive statements or predictions regarding the existence of infringement, the validity of patents, or the outcome of the litigation.
