of the patented invention (Article 70). However, the doctrine of equivalents may be employed. A patentee may grant an exclusive license (Article 77) or a non-exclusive license (Article 78). Infringement and remedies Civil remedies Right to demand an injunction The patentee may exercise a right to demand an injunction against the person who infringes or is likely to infringe its rights: Article 100(1) of the Patent Act. A “person who infringes or is likely to infringe the patent rights” in that paragraph means a person who works (Article 2(3)) a patented invention without the patentee's permission, or a person who commits an act of indirect infringement. In making a demand for an injunction under Paragraph (1) of Article 100, the patentee may also demand measures necessary for the prevention of an act of infringement, including the disposal of products constituting the act of infringement and the removal of facilities used for the act of infringement: Article 100(2). Damages Since a patent right is also a kind of property right, an act of infringement of a patent right constitutes a tort, and a patentee who sustains damages as a result of an act of infringement may demand damages from the infringer in tort (Article 709 of the Civil Code). Unlike an ordinary tortious act however, in the case of the infringement of a patent right, it is often difficult to prove the amount of the loss, as well as intent or negligence on the part of the infringer. For that reason, the Patent Act contains a special provision for calculating the amount of loss (Article 102), a provision on the presumption of negligence (Article 103), and a provision permitting the determination of a reasonable amount of loss (Article 105-3). Case law in infringement litigation Doctrine of equivalents In 1998, the Supreme Court of Japan showed in judgment the requirements for applying the doctrine of equivalents. The judgment says: even if, within the construction as indicated in the claim in the patent specification, there is a part which is different from the products, if (a) this part is not the essential part of the patented invention, (b) the purpose of the patented invention can be achieved by replacing this part with a part in the products and an identical function and effect can be obtained, (c) a person who has an average knowledge in the area of technology where this invention belongs