This article provides a concise explanation of Japan’s Opposition to a Granted Patent, covering its purpose, procedure, and key distinctions from patent invalidation trials.

1. What Is an Opposition to a Granted Patent?

Under the Opposition to a Granted Patent, any person (excluding anonymous individuals) may file an opposition to a granted patent no later than six months from the publication of a gazette containing the patent.

The procedure is document-based, and the opposition is examined by a panel of administrative judges at the Japan Patent Office (JPO). The panel may, at its own authority, consider additional evidence or reasons not initially provided by the opponent.

As of May 27, 2025, the official fee is JPY 16,500 plus JPY 2,400 per opposed claim.

2. Procedural Flow

A written opposition to grant of patent is filed using a designated form including an indication of the grounds and the necessary evidence for the opposition to a granted patent.

Once formally accepted, the case proceeds to substantive examination. If the panel identifies grounds for revocation, a notice is issued to the patentee, who may respond with written arguments or request corrections to the patent.

The JPO will then decide whether the patent should be maintained or revoked. While a revocation decision can be appealed by the patentee, there is no right of appeal against a decision to maintain the patent.

3. Grounds and Features of Examination

Opposition grounds are limited to specific public interest issues such as lack of novelty, inventive steps, or insufficient description in the patent specification.

All examinations are conducted in writing—oral hearings are not permitted.

The panel may also introduce additional evidence on its own initiative, allowing for a flexible and efficient review process.

4. Key Differences from Patent Invalidation Trials

The opposition procedure is an administrative process between the JPO and the patentee. Anyone can file an opposition.

In contrast, invalidation trials are disputes and can only be initiated by interested parties. Invalidation trials can be requested at any time and are generally more expensive.

Thus, an Opposition to a Granted Patent offers a faster and lower-cost alternative for post-grant patent review in Japan.

If you have any questions, please feel free to contact us through the following page:

https://www.oshpat.jp/en/en-contact/

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