Voting for people with intellectual disabilities has not progressed sufficiently. Two staff members who are in charge of responding to Komae City visited welfare workplaces to learn how to communicate.
If you cannot write, you can also vote using the "proxy voting" system, in which the polling station staff confirms who you will vote for and writes on your behalf. For more information on how to vote in Japan, go to: http://www.japantimes.co.uk/news/features/2013/01/29/news-features/stories/komae-council-election-training.html#storylink=cpy.