It turns out that Japanese copyright law does make provision for fair use quotations for criticism and reporting! So much for the Online Fanart Protection league's wholesale demand for permission before quoting.
(Quotations)Article 32. (1) It shall be permissible to make quotations from a work already made public, provided that their making is compatible with fair practice and their extent does not exceed that justified by purposes such as news reporting, criticism or research.
(2) It shall also be permissible for the press or other periodicals to reproduce informatory, investigatory or statistical data, reports and other works of similar character which have been prepared by organs of the State or local public entities or independent administrative organs for the purpose of public information and which have been made public under their authorship, provided that the reproduction thereof is not expressly prohibited.
