Services and Practice Areas

Services and Practice Areas

Litigation, Patent Strategies & Patent Searches


Patent litigation can be an effective business tool. Japanese patent infringement litigations are usually conducted quickly. The courts typically render a decision in about 1.5 years after a complaint is filed. There is no (or only extremely limited) discovery in Japan, so the parties are responsible for gathering their own evidence. The plaintiff has an obligation to set forth how the accused product infringes in the complaint. Consequently, the plaintiff must sufficiently understand the accused product before the litigation starts, compare the asserted claims against the accused product, and develop persuasive infringement arguments. For potential defendants, it is necessary to develop countermeasures such as non-infringement or invalidity arguments, or design-around options.

Japanese courts typically review infringement and/or validity issues first. An invalidation trial at the JPO can proceed simultaneously with infringement litigation. It is therefore necessary for a defendant to consider whether it should initiate an invalidation trial as part of its strategy. If the court decides validity and infringement in favor of the patent owner, it proceeds to assess damages.

At Ohtsuka Patent Office, before the start of any litigation we can put together a strategy that includes an assessment of the likelihood of infringement being found and the validity of the patent in question. During litigation, we assume the important role of advocating the client’s infringement, validity, and damages positions. Further, if the court requests a technical tutorial, we will give one and respond to questions from the judges and the opposing party.

In multi-jurisdictional, cross-border litigation the assertions and evidence presented in the different jurisdictions may not necessarily be the same even when they involve the same patent family. At Ohtsuka Patent Office, we have the technical and organizational capacity to work on such litigation by coordinating with overseas teams.

Patent Strategies


A patent application is a preparatory measure for deriving business from an invention. However, simply filing an application for an invention as it is conceived does not capture the full benefit of a patent. It is important to broaden the invention in consideration of a wider business strategy, and continue to review the application strategically as the examination progresses. We continually discuss these points with our clients, and provide ideas and advice as to how to achieve the best results.

Patent licensing policy must also match the business strategy of the company. Moreover, sometimes companies find that their businesses must grow into a technical field where they have few existing patents. In such cases, a strategy that includes the use of patents belonging to other companies may become necessary. We will help your company tailor your strategy using our experience and knowledge of the latest trends in intellectual property.

Patent Searches


One major cause of defeat in litigation for a patent owner is invalidation of the patent based on prior art. In Japan, the courts have the power to render judgment on the validity of a patent. Claim construction also depends greatly on known technology, thus the role of prior art references in litigation is an important one.

There are many patent and non-patent publications published in Japanese. Thus Japanese prior art can play a key role in invalidating U.S. and European patents. However, because of language issues, they can be difficult to search and review.

At Ohtsuka Patent Office, we have extensive experience in performing prior art searches. Because our patent attorneys have technical expertise as well as bilingual skills, we are able to correctly identify what needs to be searched and where to search, and come up with a focused plan that produces more fruitful results.