III. Claiming Priority Correction and Addition of Priority Claim
The Patent Act requires the information of the country and date of earlier application(s) to be provided on the Korean filing date and not later. When the applicant made a mistake, which is not uncommon, it was not easy to rectify the errors or add missing information because only obvious errors were allowed to be rectified.
Under the new law, the applicant is allowed to rectify the information related to the earlier applications provided or add one or more priority claim(s) within 16 months from the earliest priority date. The same safeguard is provided under the Patent Cooperation Treaty.
Does the new law allow the applicant who failed to declare the priority claim to claim priority belatedly? It seems not, although it is arguable. The new provision prescribes that a person "who claimed priority" according to Paragraph 1 (of Article 54) may amend or add the priority claim. The Paragraph 3 provides that the declaration of priority should be made when a patent application is filed. Thus, an applicant who failed to declare priority at the time of filing is understood not to be qualified to "add' or "amend" the non-existing priority claim. We understand that other interpretation of the new law allowing later claiming priority is possible, but we estimate its probability is not so high. (Art. 7, Art 55(5))

The Priority Document
Submission of priority document will be exempted when the earlier application has been filed in a country recognized by the Commissioner. Up to now, Japan agreed with Korea to exchange the priority documents on behalf of their applicants. We expect additional patent offices in other countries will agree to exchange priority document with Korea; thus more applicants will get exempted from the burden of submitting priority documents. (Art. 54(4))