According to a study, all Japanese citizens will share the surname Sato by the year 2531 if the country maintains the regulation requiring couples to use the same surname after marriage.
According to the head of the study, Professor Hiroshi Yoshida at the Center for Economic and Social Research on the Elderly at Tohoku University, as of 2023, Sato is currently the most common surname in Japan, with 1.529% of Japanese people carrying this name.
Professor Hiroshi Yoshida from the Center for Economic and Social Research on the Elderly at Tohoku University presents his research on surnames in Japan on March 22, 2024. (Photo: Mainichi).
Professor Yoshida conducted research and calculated two scenarios: one is that Japan maintains a common surname system among couples, and the other is the implementation of a selective individual surname system.
He utilized data available on the Myoji-yurai.net website, which provides information related to names based on government statistics and phone directories. Based on the trend of the number of people with the surname Sato, he calculated the proportion of the Japanese population that carries this name and the estimated rate of increase.
The results of Professor Yoshida’s calculations indicate that, under the current system where either spouse must adopt the same surname after marriage, the proportion of the Japanese population with the surname Sato has increased by 1.0083 times from 2022 to 2023.
Assuming this rate of increase remains constant and couples referred to as Mr. and Mrs. Sato continue to grow annually, then more than half of the population will share the surname Sato by 2446. By 2531, everyone will have the surname Sato.
According to a 2022 survey by the Japanese Trade Union Confederation involving 1,000 workers aged 20 to 59, 39.3% of singles indicated they would like to share a surname with their spouse even if a selective individual surname system were adopted. Using this figure, Yoshida determined that by 2531, only 7.96% of the population would be named Sato under the selective individual surname system, but the Sato surname would still continue to dominate by 3310.
At the same time, if Japan’s population continues to decline at the current rate, only 22 people will remain by 3310. Yoshida concludes that if a selective individual surname system is implemented, the diversity of Japanese surnames will be maintained until the population completely disappears.
After centuries of tradition requiring couples to share a surname, waves of opposition and a desire to retain individual surnames have begun to emerge in Japanese society.
Professor Yoshida emphasizes that his estimates are based on a hypothetical scenario and comments: “I empathize with their goal of bringing issues related to the selective individual surname system into numbers. If everyone shares the surname Sato, we may very well have to be called by our first names or by numbers. And I think that is not a good thing.”
