Japanese people could all be called Sato by 2531, if the country maintains its single name system. Sato is the most common surname in Japan, accounting for 1.5% of the total population.

Japan is the only country in the world to require married couples to have the same last name. Conservative members of the Liberal Democratic Party (PLD), the ruling party, say for their part that changing the law would “undermine” family unity and sow confusion among children.