The Japan Patent Office (JPO) dismissed the opposition to TM Reg no. 6945136 for the stylized mark “RUBiK Pi,” claimed by SPIN MASTER TOYS UK LIMITED, the owner of the famous “RUBIK CUBE” mark for the three-dimensional puzzle cube, by finding dissimilarity and unlikelihood of confusion between the two marks.
[Opposition case no. 2025-900188, decided on March 16, 2026]
TM Reg no. 6945136
The contested mark (see below) was filed by Thunder Software Technology Co., Ltd., a leading Chinese provider of smart operating system (OS) technologies and services, for use on computer-related goods and services in Classes 9, 41, and 42 with the JPO on December 3, 2024 [TM App no. 2024-129535].
The literal element of the mark appears to be “RUBi Pi” due to a cube design placed between two terms. However, the applicant’s website indicates the contested mark in colors to be read as “RUBIK Pi”.
The JPO examiner did not issue a notice of grounds for refusal. The mark was registered on July 4, 2025, and then published for a post-grant opposition on July 14.
Opposition by SPIN MASTER TOYS UK LIMITED
On September 16, 2025, just before the lapse of statutory opposition period for two months, SPIN MASTER TOYS UK LIMITED filed an opposition against the contested mark and claimed cancellation of its entire registration in contravention of Article 4(1)(vii), (xi), (xv) and (xix) of the Japan Trademark Law by citing the earlier marks in connection with the world-famous three-dimensional puzzle cube (Cited mark No. 1 – 6), “RUBIK CUBE”.
The claimant argued that relevant consumers and traders will consider the cube design representing the letter “K,” and thus the contested mark, to be read as “RUBIK” or “RUBIK Pi” in the course of actual business, given that the applicant’s product (a lightweight development board for AI platforms) using the contested mark is offered for sale in the name of “RUBIK Pi” on their website.
Considering that the Cited marks are famous worldwide as an indicator of the claimant’s 3D puzzle cubes, consumers would mistakenly recognize the commercial source of the goods and services in question as being from the claimant or other economically linked undertakings at the sight of the contested mark.
JPO decision
The JPO Opposition Board admitted the remarkable degree of recognition and popularity of the Cited mark Nos. 3, 5, and 6 as source indicators of the claimant’s business based on the evidence submitted by the claimant. However, the Board questioned whether the other Cited marks, which mainly consist of the term “RUBIK,” have also become famous for identifying the claimant’s source.
Regarding the contested mark, the Board found that its overall configuration would not create the sound of “RUBIK” or “RUBIK Pi.” Instead, the contested mark gives rise to the sound of “RUBi Pi,” but has no clear meaning.
Even if the Cited mark 3 “RUBIK CUBE” has become famous, relevant consumers are unlikely to associate the goods and services in question bearing the contested mark with the Cited marks due to the marks’ low degree of similarity. Therefore, the Board held that the contested mark should not be vulnerable to cancellation based on Article 4(1)(xv) of the Trademark Law.