Study forecasts 'Sato' monopoly in Japan by 2531 amid calls for marriage law reform

According to a recent study led by Hiroshi Yoshida, a professor of economy at Tohoku University, if Japan continues its insistence on couples adopting a single surname, everyone in Japan will bear the name "Sato-san" by the year 2531. Yoshida's study suggests that without reforming the current marriage law, which mandates spouses to share a surname, "Sato" will become the only surname option in Japan within the next 500 years.

Yoshida's projections, although based on several assumptions, aim to highlight the potential societal impacts of the current surname system in Japan. He emphasizes that if everyone shares the same surname, individuals might have to be distinguished by their first names or even by numbers, envisioning a less-than-ideal world. Already, "Sato" ranks as the most common Japanese surname, comprising 1.5% of the total population, closely followed by "Suzuki."

Despite some initial confusion on social media, where some mistook the study for an April Fools' Day prank, Yoshida stresses the seriousness of the issue. He warns that a nation where everyone shares the same surname would not only be inconvenient but would also erode individual dignity and lead to the loss of family and regional heritage.

Yoshida's calculations show a steady increase in the proportion of Japanese with the surname "Sato" over time. If the current trends persist and the law remains unchanged, he predicts that half of Japan's population will bear the name "Sato" by 2446, reaching 100% by 2531.

Currently, Japanese couples must decide on a shared surname upon marriage, with 95% of cases resulting in the woman changing her name. However, if the government yields to mounting pressure to allow separate surnames for married couples, the scenario could change dramatically.

An alternative scenario, based on a survey by the Japanese Trade Union Confederation, suggests that nearly 40% of employees aged 20 to 59 would opt to share a surname even if given the choice for separate ones. Under this scenario, Yoshida projects that only 7.96% of the Japanese population would bear the surname "Sato" by 2531, according to The Guardian.

Advocates for reforming the law on married surnames hope that this study will bolster their campaign. They argue that allowing separate surnames would prevent the disappearance of diverse surnames like "Suzuki," "Watanabe," and others, ultimately preserving family heritage.

While Japan has permitted maiden names to appear alongside married names on official documents, it remains the only country mandating spouses to share a surname. Conservative members of the ruling Liberal Democratic Party (LDP) oppose changing the law, citing concerns about family unity and potential confusion among children.