A new study suggests that all people in Japan could eventually share the same surname if the country’s restrictive marriage laws remain unchanged. Currently, Japan requires married couples to share the same surname, with wives typically taking their husband’s name. However, same-sex marriages are not legal in Japan, and there is a movement to change these rules led by women’s rights advocates and those seeking to preserve the diversity of Japanese surnames.
According to the study led by economist Hiroshi Yoshida, if the current rules regarding surnames continue, all Japanese people could have the surname Sato by the year 2531. Sato is currently the most common surname in Japan, followed by Suzuki and Takahashi. Yoshida, whose own surname ranks 11th most common, was commissioned by the “Think Name Project” group, which is pushing for legal changes to allow couples to keep both their last names.
However, the declining marriage rate in Japan could potentially impact this projection. The number of marriages in Japan has been steadily decreasing, with a nearly 6% decline in 2023, dropping below 500,000 for the first time in 90 years. Additionally, divorces have been increasing, further complicating the issue. Yoshida acknowledges that if fewer people marry than expected, his prediction about the proliferation of the surname Sato may not hold true.
The study also highlights the broader issue of Japan’s declining population. With a fertility rate of 1.3 – well below the 2.1 needed for a stable population – and a growing elderly population comprising 29.1% of the total, Japan is facing a population crisis. Prime Minister Fumio Kishida has warned about the implications of this demographic trend, stating that Japan is at risk of not being able to maintain social functions due to its falling birth rate.
In East Asia, including Japan, names are generally less diverse compared to Western countries. For example, in China, approximately 30% of people have one of five common surnames, and nearly 86% of the population shares just 100 surnames. This lack of diversity in naming conventions, combined with the natural process of name extinction in patrilineal societies, could contribute to the trend of a single surname becoming predominant in Japan if current laws remain unchanged.
