Effective April 1, 2015, the Japanese Patent Office is adopting a new post-grant opposition procedure. The system is being introduced to supplement the existing “invalidation trial” system, and offers to be a less costly way to challenge a recently issued Japanese patent.

In accordance with the new procedure, any person can request revocation of a patent on the basis of lack of novelty or inventive step, inadequate disclosure, and other substantive grounds. The procedure is conducted entirely in writing.

Importantly, the opposing party must file the request within six months of the issue date, and include all arguments and evidence upfront. This is a small window of time, and the short fuse is made worse because documents will need to be translated before filing.

The request is examined by a board of examiners at Japanese Patent Office. If the examiners decide that the patent is to be revoked, a notice with reasons is issued to the patent owner. The patent owner is then given an opportunity to submit arguments, and may request “correction” of the patent by narrowing the claims. The opposing party is permitted to file a reply to the patent owner’s submission, before a final decision is reached. The patent owner is provided with the right of appeal, whereas the opposing party cannot appeal the decision. However, there is no estoppel, and the same evidence can be used by the opposing party in a subsequent invalidation trial.

Companies with an allowed Japanese patent application should consider paying the issue fee immediately to obtain issuance before the April 1st start date and avoid being subject to the new system.