Looking around I'm somewhat at a loss to find any really good April Fool's stories today in Japan. Nothing on TV that I've come across and nothing seemingly in the newspapers either. Except possibly for one particular article. It's been report that the chairman of the JFA, the Japanese Football Association has offered to host the 2022 World Cup in Japan if Qatar falls completely apart.
The reason this is a questionable one is that it would mean Japan has the Rugby World Cup in 2019, the Olympics in 2020 and then the World Cup in 2022 (followed by the Women's World Cup in 2023 if that bid is also successful). So either someone is being opportunistic with the news today, or we're in for an awesome run of events over the next few years!