Japan doesn't really come up as a topic when people talk about misinformation and disinformation, but the internet in the country is not free from hoaxes and false rumors.
Last year, the Japan Center of Education for Journalists launched a collaborative verification project to monitor misinformation related to the lower house election held on Oct. 22.
The blog post below provides details of what types of false content disseminated and how. We focused on election-related content and it's only a fraction of the "fake news" ecosystem in the country but worth reading given little research has been done in Japan (The project was about a year ago but took us until now to translate the article into English!).
For details of how our project ran, I wrote a piece about how this project ran on First Draft in 2017.
... And please also see other article that mention the project.