Japan Emerges as a Key Venue for High-Stakes SEP Litigation and Patent Enforcement

Japanese courts have recently demonstrated a marked shift toward more robust patent enforcement, highlighted by substantial damage awards and evolving jurisprudence on standard essential patents (SEPs). This change follows a period of relative dormancy in SEP litigation since the landmark Apple v Samsung decision in 2014.

A pivotal moment came in 2025 with the Intellectual Property High Court’s ruling in Toray v Sawai Pharmaceutical & Fusō Pharmaceutical Industries, where damages exceeding ¥20 billion were awarded in a pharmaceutical patent infringement case. This amount nearly triples the previous record of approximately ¥7.4 billion set in 2002, underscoring a new era of serious financial consequences for patent infringement in Japan.

Statistical data from the Intellectual Property High Court reveals that patentees prevailed in about 31% of patent infringement judgments from 2016 to 2025. When settlements effectively favoring patentees are included, the success rate approaches 40%. Moreover, the proportion of judgments awarding damages of at least ¥100 million rose from 22% during 2014-2019 to 42% in 2020-2023 in Tokyo and Osaka District Courts, indicating enhanced effectiveness of patent enforcement.

While average damages in Japan remain lower than those typically awarded in the United States, the comparatively lower litigation costs and the absence of a strict eBay standard for injunctive relief make Japan an appealing forum for patent enforcement. These factors encourage patent owners to consider Japan alongside the US, Europe, and China for coordinated global litigation strategies. In some cases, Japan may serve as a standalone venue for resolving patent disputes.

The strategic importance of SEPs has grown alongside the expansion of IoT and telecommunications technologies. SEPs are not only licensing revenue sources but also critical assets underpinning broader business strategies. However, SEP disputes are often complex and cross-border, necessitating a dispute resolution framework that ensures predictability and effective outcomes through both court proceedings and alternative dispute resolution (ADR).

Japanese courts have issued several important decisions on SEPs in recent years, accompanied by the publication of litigation and mediation guidelines by the Tokyo District Court’s IP Division. These developments provide clearer pathways for resolving SEP disputes within Japan.

Historically, the 2014 Apple v Samsung Grand Panel decision set a stringent standard for determining whether an implementer was unwilling to take a license on fair, reasonable, and non-discriminatory (FRAND) terms. The court emphasized that claims for damages exceeding FRAND royalties require exceptional circumstances, which implementers could leverage to prolong negotiations. This approach diminished Japan’s attractiveness as a forum for SEP enforcement.

Additionally, the Apple v Samsung decision applied a damages calculation method that resulted in relatively low compensation compared to international FRAND licensing norms. The court multiplied infringing product sales revenue by the proportion attributable to standard compliance and then by the patent’s contribution ratio, yielding a modest damages figure.

A significant shift occurred with the Tokyo District Court’s ruling in Pantech v Google, where the court found Google to be an unwilling licensee. Google’s refusal to disclose sales data necessary for royalty calculations and its conduct during settlement negotiations led the court to reject Google’s abuse-of-rights defense and grant an injunction. This ruling signals a tougher stance on implementers’ unwillingness to license on FRAND terms.

However, a parallel case in the Osaka District Court involving the same parties and SEP reached the opposite conclusion shortly after the Tokyo decision. The Osaka court limited its assessment period for willingness to license to three months after the lawsuit filing and did not consider post-settlement negotiation conduct, illustrating some divergence in judicial approaches within Japan.

These recent rulings and procedural guidelines collectively indicate a revitalized and more assertive patent litigation environment in Japan, particularly concerning SEPs. For patent holders, Japan now offers a viable and potentially advantageous forum for enforcing patent rights and resolving complex SEP disputes in a global context.