1. As to the grounds of appeal Nos. 1 to 3

(a) If two or more persons have created a single work, in which case they cannot separately use the part of their respective contributions by jointly contributing to the creative expression form itself with the intention of joint creation, they shall be the co-authors of the work.

Here, the intention of joint creation does not mean the intention to become a joint author legally, but it means the intention to create a single work that can not be separately used due to a joint creation act (see Supreme Court Decision 2012Do1606, Dec. 11, 2014). In a case where two or more persons contribute to the creation of a single work in consecutive order by contributing to the creation of a single work in a different period of time, the previous author wishes to complete a single work, the use of which is impossible by modifying the subsequent author’s original work is not completed in a situation where the previous author’s creation is not completed as a single work, and if the latter author wishes to complete a single completed work that is impossible to be separated and used by expanding or decreasing the original work based on the creation of the previous author’s original work, it can be recognized that they have the intention to jointly create a single work that is to complete a single work by mutual supplement of each creative part.

On the other hand, if the prior author does not have the above intent, but only intends to make a work completed by his own creation, it is impossible to separately use a single work due to the increase or decrease, etc. of the subsequent author when the creation portion of the prior author was not completed as a single work.

Even if there is an intention of joint creation between the preceding author and the latter author.