About Us Contact Us Privacy Policy
© GOOD Worldwide Inc. All Rights Reserved.

In 500 years, every citizen in Japan could strangely have the same surname

The surname 'Sato' could take over the majority of the population in Japan in the coming years, a worrisome issue for the country.

In 500 years, every citizen in Japan could strangely have the same surname
Cover image source: Weekend crowds shop on Takeshita Street in Tokyo. (Photo by James Leynse/Corbis via Getty Images)

Japan has earned its reputation as the global epicenter of tech innovation over the years. The island nation has produced eye-catching technology with the help of precision engineering and cutting-edge electronics. While the country has made its name for technology, its civilization may be hit by one of the worst crises in the distant future and it is largely related to surnames. In a recent simulation conducted by Tohoku University economics professor Hiroshi Yoshida, it has been found that by the year 2531, almost all Japanese citizens will share one common surname—Sato, reports The Japan Times.

Image source: Pexels | Photo by Aleksandar Pasaric
Image source: Pexels | Photo by Aleksandar Pasaric

Japan is the only country in the world that requires spouses to use the same last name, following an archaic civil code from 1898. As of 2023, the most common last name in Japan was Sato, accounting for about 1.5% of the total population. While this might seem insignificant, the study conducted by Yoshida has forecasted that if this continues, every Japanese person will be known as Sato by 2531.

The study was organized by the Think Name Project and Asuniwa as they want to legalize the opportunity to select surnames in the country. This study led to a hypothesis suggesting that if no changes are made to the surname policies, then 50 percent of family names in Japan will be Sato by 2446. The annual growth rate of the surname Sato is thought to be increasing by 1.0083 percent, according to data between 2022 and 2023.

Image source: Pexels | Photo by Ryutaro Tsukata
Image source: Pexels | Photo by Ryutaro Tsukata

Professor Yoshida told The Mainichi, a Japanese Newspaper, about the possible consequences of Sato taking over the Japanese civilization. He said, "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."

If Japan introduces a separate surname system, only 7.96% of the population will have the last name Sato in 2531. However, the surname will still take over the population by the year 3310. Another parameter taken into account was the declining Japanese population. According to the source, if the Japanese population keeps declining at the current speed, only 22 people will be left in 3310. As per Professor Yoshida, the diversity of Japanese surnames will be maintained until the population ceases to exist, only if a separate surname system is introduced.


Some social media users assumed that the study was an April Fools' Day prank but Professor Yoshida wanted people to give it a thought. According to Asahi Shimbun, a Japanese newspaper, Yoshida said, "Everyone having the same surname will not only be inconvenient but also undermine individual dignity." He added, "This would also lead to the loss of family and regional heritage associated with surnames."

In June 2021, Japan's Supreme Court announced that laws stipulating Japanese couples to choose one family name were constitutional after a petition was filed asking for a change to the century-old tradition. This challenge to the policy 'One family, One name' has forced married couples to share the same family name.

More Stories on Good