The current law obliges one of the two spouses to adopt the surname of the other. Hiroshi Yoshida, professor of economics at Tohoku University, says the Japanese should all have the surname Sato in the year 2531.
The study was initially taken as an April Fool's joke before the researcher seriously explained his calculation method. The subject of changing one's name has become consensual between the sexes. But the political class, attached to the traditional notion of family, refuses to reform the law.