Shenzhen Liqiu Sanhou Technology Co Ltd v. Xiaoling Che

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Shenzhen Liqiu Sanhou Technology Co., Ltd. (China)
  • Defendant: Xiaoling Che (China)
  • Plaintiff's Counsel: Glacier Law LLP
• Case Identification: 1:24-cv-11980, N.D. Ill., 04/15/2026
• Venue Allegations: Plaintiff alleges venue is proper because Defendant targets consumers in Illinois through the Amazon e-commerce store and has purposefully availed himself of the district by previously filing a patent infringement lawsuit against other Amazon sellers in the same court.
• Core Dispute: Plaintiff seeks a declaratory judgment that its "Puzzle Board" product does not infringe Defendant's patent for a movable puzzle platform, and that the patent is invalid.
• Technical Context: The technology relates to rotatable platforms designed to assist users in assembling large jigsaw puzzles by allowing the work surface to move, rather than requiring the user to move around a stationary table.
• Key Procedural History: The action was precipitated by a notice from Amazon.com, which removed Plaintiff's product listings following an infringement complaint filed by Defendant. Defendant previously initiated litigation in the same district against other Amazon sellers for infringement of the same patent family.

Case Timeline

Date	Event
2021-09-26	U.S. Patent No. 11,890,551 Priority Date
2024-02-06	U.S. Patent No. 11,890,551 Issue Date
2024-11-14	Plaintiff receives Amazon takedown notice for accused products
2026-04-15	Second Amended Complaint for Declaratory Judgment filed

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

• Patent Identification: U.S. Patent No. 11,890,551, "Movable Puzzle Platform," issued February 6, 2024. Compl. ¶16

• The Invention Explained:

  • Problem Addressed: The patent's background describes the inconvenience of assembling large-scale jigsaw puzzles, which often requires a large playing surface that forces the user to physically move around the table to reach different sections. '551 Patent, col. 1:40-55
  • The Patented Solution: The invention is a platform for puzzle assembly, consisting of a puzzle board and a "board accessible unit" attached to its underside. '551 Patent, abstract This unit, typically a turntable mechanism, allows the entire puzzle board to both slide and rotate freely on a surface, enabling the user to bring any section of the puzzle toward them without changing their own position. '551 Patent, col. 3:8-13 '551 Patent, col. 5:10-24
  • Technical Importance: The patented solution aims to improve the ergonomics and convenience of playing large puzzles by making the workspace itself mobile. '551 Patent, col. 2:10-18

• Key Claims at a Glance:

  • The complaint asserts non-infringement of independent claim 1. Compl. ¶19
  • The essential elements of independent claim 1 are:
    • A puzzle board with a top surface.
    • A board accessible unit comprising a first moving member coupled to the puzzle board, a second moving member, and a first bearing unit between them.
    • The first moving member is rotatably mounted to the second via the bearing unit, allowing the puzzle board to self-rotate.
    • The second moving member has a flat base with a central protrusion that engages the bearing unit.
    • An outer circumferential surface of the first member engages an inner circumferential surface of the second member via the bearing unit, enabling coaxial rotation.
  • The complaint notes that because independent claim 1 is not infringed, dependent claims 2-6 are likewise not infringed. Compl. ¶24

III. The Accused Instrumentality

• Product Identification: Plaintiff's "Puzzle Board," sold under the brand name "Playboda" with ASINs B0CQSZMJBS and B0C7QFLV8L. Compl. ¶11 Compl. p. 6

• Functionality and Market Context:

  • The accused product is a puzzle board system that includes a turntable mechanism. The complaint's non-infringement arguments focus on the specific construction of this turntable. It alleges the turntable is a free-standing unit not physically "coupled" to the board. Compl. ¶20 The complaint further alleges the turntable's components differ structurally from those claimed, for instance, by having an "uneven base" with a groove instead of a "flat base" Compl. ¶21, and by using "snap-fit" arms for engagement rather than the claimed mechanism of circumferential surfaces engaging via a bearing unit Compl. ¶22
  • The complaint alleges the Amazon marketplace is Plaintiff's "primary sales channel into the United States" and that the removal of its listings has caused "immediate and irreparable harm." Compl. ¶13

IV. Analysis of Infringement Allegations

The following table summarizes the Plaintiff's arguments for non-infringement as presented in the declaratory judgment complaint.

'551 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Non-Infringing Functionality	Complaint Citation	Patent Citation
a board accessible unit comprising a first moving member coupled with said puzzle board...	The accused product's turntable is a free-standing unit that is "not coupled with the main body of puzzle board"; the board simply rests on top of it. A provided image shows the turntable being lifted away from the board as a separate component.	¶20; p. 6	col. 4:26-28
the second moving member having a flat base and a protrusion protruded from the center of the flat base...	The accused product's second moving member does not have a flat base. Instead, it has an "uneven base" featuring a distinct "groove for accommodating bearing balls."	¶21; p. 6	col. 8:47-50
wherein an outer circumferential surface of said first moving member is engaged with an inner circumferential surface of said second moving member via said first bearing unit...	The moving members are engaged via a "snap-fit structure." The complaint alleges the outer and inner circumferential surfaces "do not come into contact at all," and thus cannot be engaged via the bearing unit as claimed. An annotated image highlights a "gap" between these surfaces.	¶22; p. 8	col. 5:45-53

• Identified Points of Contention:
  • Scope Questions: A primary dispute will be the proper construction of "coupled with." The case raises the question of whether placing a board on a separate, free-standing turntable meets the "coupled with" limitation, or if the term requires some form of physical attachment (e.g., adhesive, magnets, screws), as some embodiments in the patent suggest. Compl. ¶20 '551 Patent, col. 6:25-59
  • Technical Questions: A key factual question is whether the accused product's base, which contains a groove for ball bearings, can be considered a "flat base" under any reasonable interpretation. Compl. ¶21 Similarly, the court will have to determine if the accused product's "snap-fit arm" engagement is structurally and functionally different from the claimed engagement of circumferential surfaces "via" a bearing unit. Compl. ¶22

V. Key Claim Terms for Construction

• The Term: "coupled with"

  • Context and Importance: Plaintiff's core argument is that its turntable is a separate component that the board merely rests upon, and is therefore not "coupled." Compl. ¶20 The patentee will likely argue for a broader functional definition. Practitioners may focus on this term because its construction could be dispositive of the infringement question.
  • Intrinsic Evidence for a Broader Interpretation: The specification discloses embodiments where the coupling is detachable, using methods like magnetic attraction or self-adhering film, which might support an argument that "coupled" does not require permanent integration. '551 Patent, col. 6:25-59
  • Intrinsic Evidence for a Narrower Interpretation: The patent figures and primary descriptions generally depict the board accessible unit being directly affixed to the bottom of the puzzle board. '551 Patent, FIG. 2 '551 Patent, col. 4:26-28 This could support an interpretation requiring a direct physical attachment.

• The Term: "flat base"

  • Context and Importance: Plaintiff provides photographic evidence of its product's "uneven base" to argue it falls outside the literal scope of this term. Compl. ¶21 The materiality of this structural difference will be a point of contention.
  • Intrinsic Evidence for a Broader Interpretation: The patent does not provide a special definition for "flat base," suggesting it should be given its plain and ordinary meaning. The patentee may argue that "flat" is a general descriptor of the support surface and does not preclude minor features like a bearing race.
  • Intrinsic Evidence for a Narrower Interpretation: The claim language recites "a protrusion protruded from the center of the flat base." '551 Patent, col. 8:47-48 This phrasing may imply a generally planar surface from which a distinct feature protrudes, arguably contrasting with a surface defined by a continuous groove as shown in the complaint. Compl. p. 6

VI. Other Allegations

The complaint seeks a declaratory judgment of invalidity on several grounds:

• Anticipation/Obviousness (§§ 102/103): The complaint alleges that all claims of the '551 Patent are invalid as anticipated or obvious in view of five cited prior art publications. Compl. ¶¶29-35
• Lack of Written Description and Enablement (§ 112(a)): Plaintiff alleges that the limitation concerning "a protrusion protruded from the center of the flat base...for engaging with the first bearing unit" is not adequately described or enabled, as the patent allegedly fails to provide sufficient detail on its structure, dimensions, or functional interaction. Compl. ¶¶36-37
• Indefiniteness (§ 112(b)): The complaint argues that key phrases, including "for engaging with the first bearing unit" and the mechanism of engagement between the circumferential surfaces, are ambiguous and fail to inform a person of ordinary skill in the art about the scope of the invention with reasonable certainty. Compl. ¶¶38-39

VII. Analyst's Conclusion: Key Questions for the Case

• Definitional Scope: The central issue is one of claim construction. The case will turn on whether the term "coupled with" requires physical attachment or can be read on a board simply resting on a turntable, and whether "flat base" can encompass a surface with a significant structural groove.
• Structural Mismatch: A key evidentiary question will be whether the accused product's "snap-fit" mechanism for connecting its rotating members is fundamentally different from the claimed method of engagement "via said first bearing unit." The complaint's visual evidence of a "gap" between the relevant surfaces will be a focal point of this analysis.
• Invalidity as a Parallel Defense: Beyond the non-infringement arguments, the strength of the Plaintiff's invalidity case, particularly the indefiniteness challenges under § 112 that target the same claim terms central to the infringement dispute, presents a significant secondary battlefront for the court to resolve.