1. Article 5(1) of the Copyright Act provides that “a creative work produced by means of translation, arrangement, alteration, color, image, etc. of an original work” is “a derivative work.” In order to become a derivative work, an increase or decrease should be made based on the original work, but actual similarity should be maintained with the original work.

Therefore, in a case where a summary based on an original work, which is a literary work, becomes a new independent work that does not have any substantial similarity with the original work, it does not constitute an infringement on the copyright holder of the original work’s right to create a derivative work (see, e.g., Supreme Court Decision 2007Da63409, Feb. 11, 2010). Here, whether a summary has any substantial similarity with the original work should be determined by comprehensively taking into account the following: (a) whether the summary maintains the outline, structure, main structure, etc. that serves as the basis of the original work; (b) whether the summary selects only a part of the sentences that form the original work; and (c) whether the summary is merely merely an abstract or an abstract expression of the abstract sentences that merely selected a part of the sentences that form the original work; (d) whether the summary is the relative quantity

On the other hand, the subject of copyright protection is a creative expression form that explicitly expresses human thoughts and emotions through speech, text, sound, color, etc., and the contents expressed therein, i.e., ideas or emotions, such as ideas or theories, do not, in principle, be protected. Thus, in determining whether there exists a substantial similarity between two copyrighted works in order to determine whether a copyright has been infringed, it shall be compared only with a creative expression form, and it shall not be taken into account whether the ideas or emotions, other than the expression form, are unique.