A “derivative work” under the Copyright Act of Japan means
a workcreated by translating, arranging musically (composing as a musical arrangement)or reformulating (transforming) a pre-existing work(an original work), or dramatizing, cinematizing (making into a cinematographic work)or otherwise adapting a pre-existing work(an original work). The protection ofa derivative work does not affect the rights of an author of the original work.
The author of a workhas the exclusive right to create such a derivative work. And in connection with the exploitation of a derivative work, an author of its original work has exclusive rights of the same types as those owned by an author of the derivative work. Consequently, if you want to use(e.g. reproduce and publish) a translation or an adaptation(i.e. a derivative work from an original work), you must obtain permission from both the copyright owner of the original work and of the derivative work.
Kaneda Copyright Agency
For proper copyright management in Japan