In Japan the law provides that matters relating to the validity of patents should be dealt with by nullity proceedings initiated before the Patent Office. Invalidity of the patent being sued upon is not in itself a defense to an infringement lawsuit in Japan, although on occasion, courts have construed patents narrowly in cases where they have felt the patent unlikely to be valid. As a practical matter, this situation may be about to change. In April 2000 in Texas Instruments v. Fujitsu Ltd. the Japanese Supreme Court held that, in cases where a court hearing an infringement action concluded that it was highly likely that the patent was invalid, it could decline to enforce it, since any such enforcement would be a misuse of the patent right. It therefore appears that defendants will now have a clear interest in raising issues of invalidity when sued for patent infringement. The case in which the issue arose was one where the ground of invalidity in question was the Japanese equivalent of double patenting and was fairly easy for the court to understand. Whether courts will be willing to consider issues of obviousness or other more complex allegations of invalidity in infringement trials remains to be seen. In such cases it may still be necessary to use the traditional route of a nullity suit.