The bizarre rule that means everyone in Japan could one day have the same surname

The last name ‘Sato’ could rule Japan within 500 years (Picture: Getty)

Imagine everyone in a country with 125,000,000 people having the exact same last name.

That’s what could end up happening in Japan due to a law that requires married couples to take the same last name.

The last name ‘Sato’ is currently the most popular family name in Japan, with more than 1.5% of the population using it.

The proportion of those with the last name grew 1.0083 times between 2022 and 2023, and if it continues, more than half of the country will have that last name by 2446.

And by 2531, the entire country will share the last name ‘Sato’ – unless legislation is changed.

Professor Hiroshi Yoshida, at Tohoku University, led the recent study which made the discovery.

Japan is the only country in the world that requires married couples to have the same surname (Picture: Getty)

He told Sky News: ‘If everyone becomes Sato, we may have to be addressed by our first names or by numbers. I don’t think we can call that a good world to live in.

‘This would also lead to the loss of family and regional heritage associated with surnames.’

Japan is the only country in the world that requires married couples to have the same surname.

Top ten surnames in Japan


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The law was made in 1898, and was upheld in 2015 at Japan’s supreme court after three women argued the law infringed on ‘personal dignity’.

The law dates back to Japan’s ‘Meiji’ era, when it was introduced as part of the feudal family system which keeps women and children under the male head of the family.

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