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

A study led by Hiroshi Yoshida, an economist at Tohoku University, warns of a future where all Japanese citizens share the surname "Sato-san" by 2531 if Japan maintains its requirement for couples to adopt a single surname. This prediction underscores the urgent need for reform in Japan's marriage laws to prevent the dominance of the "Sato" surname over the next five centuries.

Yoshida's research, though speculative, sheds light on the societal consequences of Japan's current surname system. He suggests that a uniform surname could lead to individuals being identified by their first names or even assigned numerical identifiers, painting a bleak picture for societal identity. Already, "Sato" stands as Japan's most common surname, representing 1.5% of the population, closely followed by "Suzuki."

Despite initial confusion on social media, Yoshida stresses the seriousness of the issue, highlighting the potential inconvenience and loss of individual and cultural identity in a nation where everyone shares the same surname. His calculations reveal a continuous rise in the proportion of Japanese with the surname "Sato" over time, with projections indicating a complete takeover by 2531 if current trends persist.

Presently, Japanese couples must decide on a shared surname upon marriage, with the majority opting for the woman to change her name. However, there's potential for change if the government responds to growing pressure to allow separate surnames for married couples, which could significantly alter the demographic landscape, according to The Guardian.

An alternative scenario, based on a survey by the Japanese Trade Union Confederation, suggests that a considerable portion of the population would still choose to share a surname even if given the option for separate ones. Yoshida's projections under this scenario indicate a lower percentage of the population bearing the "Sato" surname by 2531.

Advocates for surname reform view this study as critical support for their cause, arguing that preserving diverse surnames like "Suzuki" and "Watanabe" is essential for maintaining family heritage.

Despite Japan's allowance for maiden names on official documents, it remains the sole country mandating spouses to share a surname. Opposition from conservative members of the ruling Liberal Democratic Party (LDP) is rooted in concerns about family unity and potential confusion among children, further complicating efforts for legal reform.