In 500 years, everyone in Japan will have the surname "Sato" if the current practice of requiring married couples to share the same last name continues, it has been forecast.

The simulation, organized by the Think Name Project and Asuniwa, was conducted by Hiroshi Yoshida, a Tohoku University economics professor with expertise in the graying of society, in a bid to show a possible future where separate surnames for married couples are not allowed. The project is a part of a campaign, designed to coincide with April Fools’ Day, to raise awareness of the implications of not amending the law requiring married couples to share the same surname.

Everyone in Japan would have “Sato” as their surname by 2531, the forecast found.