Yamazaki Mazak Corporation v Interact Machine Tools (NSW) Pty Limited

Yamazaki Mazak Corporation sought special leave to appeal from a decision of the Full Federal Court concerning patent law. The dispute involved Interact Machine Tools (NSW) Pty Limited and International Machine Tools Pty Limited, and Nakamura-Tome Precision Industry Co Limited. The core issue revolved around the concept of "fair basis" in patent law, particularly in relation to priority dates.

The High Court was required to determine whether the claims made in a patent application were fairly based on the earlier provisional or convention (Japanese) specifications. This determination was crucial because the priority date of a patent dictates the point in time against which its validity, including novelty and obviousness, is assessed. If the claims were not fairly based on the earlier documents, the patentee might be deprived of the earlier priority date, potentially rendering their own subsequent publications as prior art against their own patent.

The applicant argued that the court below erred by identifying an essential feature of the invention from the body of the specification rather than from the claims themselves. The applicant contended that the court should have focused on whether the claims, as drafted, were fairly supported by the disclosures in the provisional or convention application. This principle, the applicant submitted, applies equally to provisional specifications and international convention applications, allowing for development of the invention within a specified period while retaining an earlier priority date, provided the claims remain fairly based on the initial disclosure.