DCT

3:25-cv-10851

Shenzhenshi Wangsi Keji Youxiangongsi v. Hung

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:25-cv-10851, N.D. Cal., 12/19/2025
  • Venue Allegations: Venue is alleged to be proper in the Northern District of California because the defendant, YVONNE HUNG, is an individual who resides in the district.
  • Core Dispute: Plaintiffs seek a declaratory judgment that Defendant’s patent related to stacking stools is invalid, following Defendant’s patent infringement complaints to Amazon that resulted in the removal of Plaintiffs’ product listings from Amazon’s U.S. marketplace.
  • Technical Context: The technology concerns space-saving furniture, specifically a set of stools designed to nest together to form a single, enclosed side table, addressing storage challenges in compact living environments.
  • Key Procedural History: The complaint alleges that the defendant, the patent owner, submitted infringement complaints to Amazon against the plaintiffs. These complaints prompted Amazon to remove or deactivate the plaintiffs' product listings, establishing the "actual case or controversy" required for the court to hear this declaratory judgment action.

Case Timeline

Date Event
2022-06-15 ’715 Patent Priority Date
2025-07-29 ’715 Patent Issue Date
2025-11-14 Defendant allegedly submits infringement complaint to Amazon regarding Plaintiff Wangsi Keji's products
2025-11-21 Defendant allegedly submits infringement complaints to Amazon regarding Plaintiffs Wangsi Keji's and Yaqi's products
2025-12-11 Defendant allegedly submits infringement complaint to Amazon regarding Plaintiff Yunhanghui Keji's products
2025-12-19 Complaint for Declaratory Judgment of Invalidity Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 12,369,715 - *"Stacking Stools"*

  • Patent Identification: U.S. Patent No. 12,369,715, "Stacking Stools," issued July 29, 2025 (the "’715 Patent").

The Invention Explained

  • Problem Addressed: The patent’s background section notes that conventionally stacking stools on top of one another creates a tall, potentially unsafe, and "neither spatially nor aesthetically optimal" stack, particularly in smaller living spaces like apartments (’715 Patent, col. 1:12-20).
  • The Patented Solution: The invention is a set of stools that nest together to form a single, enclosed, and functional piece of furniture, such as a side table (Compl. ¶1; ’715 Patent, col. 1:21-24). The set typically includes a top stool, a bottom stool, and one or more middle stools of a shorter height (’715 Patent, col. 2:24-30). To form the enclosed table, the bottom stool is inverted, and the middle stools are nested within the space created between the legs of the top stool and the inverted bottom stool, as illustrated in Figure 3 (’715 Patent, col. 3:9-20).
  • Technical Importance: This design allows for the "concealed storage of extra seating" in a form that appears as a single piece of functional furniture, which is described as "particularly advantageous for small spaces and apartment living" (’715 Patent, col. 4:24-29).

Key Claims at a Glance

  • The complaint’s invalidity allegations focus on independent claim 1 (Compl. ¶27).
  • The essential elements of claim 1 include:
    • A top stool, a first middle stool, a second middle stool, and a bottom stool, each with a platform and a plurality of legs.
    • A configuration where the middle stools are "nested within the top stool and the bottom stool when the bottom stool is inverted."
    • A series of co-planarity limitations, such as "a top surface of each of the plurality of top legs is co-planar with the bottom surface of the top platform."
    • A requirement that "the plurality of top legs, the plurality of bottom legs, the plurality of first middle legs, and the plurality of second middle legs all have a same length."
  • The complaint seeks a declaration that "the claims" of the patent are invalid, suggesting a potential challenge to all claims (Compl., Prayer for Relief ¶A).

III. The Accused Instrumentality

Product Identification

  • The complaint identifies "nesting furniture products" sold by the three plaintiffs on Amazon.com through their respective storefronts: "WoodsWhisper," "Yunhanghui" (with products branded "Mansfieler"), and "AnywaysWood" (with products branded "AnywaysWood" and "KungFuWood") (Compl. ¶¶12-14). The complaint also lists several specific Amazon Standard Identification Numbers (ASINs) for the removed product listings (Compl. ¶¶15-17).

Functionality and Market Context

  • The complaint does not provide technical details about the functionality of the plaintiffs' products beyond describing them as "nesting furniture." The core of the allegations regarding the products is commercial; specifically, that the defendant's infringement assertions to Amazon "impaired" the plaintiffs' ability to sell their products in the United States market, leading to the de-listing of the products and creating the controversy at issue (Compl. ¶¶6, 20).

IV. Analysis of Invalidity Allegations

The complaint does not contain direct infringement allegations or a claim chart, as it is an action for declaratory judgment of invalidity. Instead, it outlines the basis for the legal controversy between the parties and makes several allegations that the ’715 Patent is invalid.

The controversy arises from infringement complaints allegedly submitted by the defendant, Yvonne Hung, to Amazon (Compl. ¶¶15-17). The defendant is identified as the founder of "Otelier," a furniture studio, and is alleged to have submitted the complaints that resulted in Amazon removing or deactivating Plaintiffs' product listings (Compl. ¶¶15, 19).

The complaint asserts that the claims of the ’715 Patent are invalid for failing to meet the requirements of 35 U.S.C. §§ 102, 103, and 112 (Compl. ¶25). The specific invalidity theories alleged are:

  • Anticipation and Obviousness (§§ 102/103): The complaint alleges the claims are anticipated or rendered obvious by prior art, listing four specific references: U.S. Patent Application Publication No. 2018/0236365, German Patent Application Publication No. DE3835170A1, Chinese Patent Application Publication No. CN112932150A, and Chinese Utility Model Patent No. CN205457293U (Compl. ¶26). The complaint does not, however, provide any analysis of how these references allegedly invalidate the patent claims.
  • Lack of Written Description (§ 112): The complaint alleges that claim 1 is invalid for lacking adequate written description for the limitation requiring that "the plurality of top legs, the plurality of bottom legs, the plurality of first middle legs, and the plurality of second middle legs all have a same length" (Compl. ¶27).
  • Lack of Enablement (§ 112): The complaint further alleges claim 1 is invalid for lack of enablement, arguing that the specification does not enable a person of ordinary skill to make and use the invention without undue experimentation with respect to the various "co-planar" limitations (e.g., "a top surface of each of the plurality of top legs is co-planar with the bottom surface of the top platform") (Compl. ¶27).

No probative visual evidence provided in complaint.

V. Key Claim Terms for Construction

  • The Term: "all have a same length"

    • Context and Importance: This term, which applies to all legs on all four stools in the claimed furniture set, is the subject of the complaint's written description challenge (Compl. ¶27). The dispute will center on whether the patent’s specification provides adequate support for the absolute requirement that all sixteen legs (in an embodiment with four legs per stool) are of identical length.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: A party defending the patent may argue that "same length" should be understood by a person of ordinary skill to include minor, inevitable manufacturing tolerances.
      • Evidence for a Narrower Interpretation: The complaint’s focus on this term suggests a potential argument that the specification does not describe an embodiment where every leg across all different stool types is identical. The specification discloses that "the length of all of the legs may be substantially equal" (’715 Patent, col. 3:6-8). The difference between the claim language ("same length") and the specification's disclosure ("substantially equal") may be a central point of contention in claim construction and the associated validity analysis.

  • The Term: "co-planar"

    • Context and Importance: This term appears in multiple limitations of claim 1 and forms the basis of the complaint's enablement challenge (Compl. ¶27). The construction of this term will be critical to determining whether the patent sufficiently teaches how to make the claimed invention. Practitioners may focus on this term because achieving perfect planarity across separate, manufactured components can be a significant technical challenge.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent owner may argue that "co-planar" in the context of furniture implies functional, not mathematical, planarity, allowing for slight variations that do not affect the utility of the stool.
      • Evidence for a Narrower Interpretation: The plaintiffs may argue for a stricter definition, contending that the specification provides no guidance, dimensions, or techniques for achieving the claimed co-planarity, thereby failing to enable the full scope of the claim without undue experimentation (Compl. ¶27). The specification describes legs being attached to platform surfaces but does not detail the method for ensuring the required planar alignment (’715 Patent, col. 2:47-49).

VI. Analyst’s Conclusion: Key Questions for the Case

  • A central issue will be one of specification support and enablement: Does the disclosure in the ’715 Patent adequately describe and enable the specific limitations recited in claim 1? The case may turn on whether a person of ordinary skill in the art would understand the patent to teach an invention where all legs across four distinct stools have the "same length" and where multiple surfaces achieve the required "co-planar" alignment without undue experimentation.
  • A second key question will be validity over the prior art: Do the four prior art references cited in the complaint, or any other prior art, disclose the elements of the claimed invention? This will be a factual inquiry dependent on a detailed comparison of the prior art teachings to the patent's claim limitations.