News Release

The rates of unique names increased in Japan over the 40 years from the 1980s: long-term analysis of baby names published in municipality newsletters

A new study evaluating historical changes in the rates of unique names in Japan from 1979 to 2018 found rising trends of individualism

Peer-Reviewed Publication

Tokyo University of Science

Timeline of present and previous research on unique baby names in Japan

image: Previous research on the rise of unique baby names in Japan has focused on the period between 2004 and 2018. Expanding on these findings, the present study examined these trends over a longer period of 40 years, from 1979 to 2018. view more 

Credit: Yuji Ogihara from Tokyo University of Science

Previous research has analyzed baby names displayed by private companies and indicated that the rates of unique names increased in Japan between 2004 and 2018 (Ogihara, 2021; Ogihara et al., 2015). However, changes over a longer period were not analyzed because of the lack of a comprehensive and systematic database on baby names in Japan, unlike in other nations such as the United States and China. Therefore, it was unclear whether this increase in unique names was recent or had occurred before the 2000s. There was a possibility that the increase in unique names were found only after the 2000s.

Examining whether the rates of unique names increased for a longer period provides a better understanding of not only historical changes in names and naming practices, but also cultural changes toward greater individualism which emphasizes uniqueness and independence.

To this end, Assistant Professor Yuji Ogihara of Tokyo University of Science and Atsuki Ito of Hitotsubashi University collected baby names from municipality newsletters and investigated historical changes in the rates of unique names in Japan over a longer period. Municipalities share important information such as major events (e.g., sports activities, lecture meetings), services (e.g., educational, medical), and basic statistics (e.g., financial, population) in newsletters. In these newsletters, the names of persons who are born, die, and marry in each municipality are listed.

For their study, the researchers collected municipality newsletters that fulfilled some criteria. The municipalities surveyed were geographically diverse. They were located all over Japan, from the southern part (Kyushu) to the northern part (Hokkaido). Some municipalities were located near the coast, while others were inland. The municipalities were also demographically diverse. They were located in both rural and urban areas.

The researchers analyzed 58,485 baby names published in these municipality newsletters between 1979 and 2018. They calculated the rates of the names that were not duplicated in each of the municipalities in each year. Then, they analyzed their historical changes. Furthermore, they calculated the rates of unique names not only within a given year (e.g., 2000) but also within a three-year unit (the target year, the year before it, and the year after it; e.g., 1999, 2000, 2001), and performed the same analysis.

They found that the rates of unique names increased within both time frames. Thus, unique names increased not only after the 2000s, but also from the 1980s for 40 years. This result shows that parents increasingly gave unique names to their babies and that Japanese culture increasingly emphasized uniqueness and independence for the 40 years, providing further evidence of the rise in uniqueness-seeking and individualism in Japan. This finding is also consistent with prior studies showing the rise in individualism in other aspects such as family structure and values.

Moreover, the findings reported in previous research (Ogihara, 2021; Ogihara et al., 2015) were replicated in this study: unique names increased in Japan in the 2000s and 2010s. In addition, the rates of unique names increased more rapidly for girls than for boys. This result may suggest that parents came to have stronger hope for their daughters to become unique and independent than for their sons. This means that the same phenomena were observed in a dataset different from that analyzed in previous research, indicating that the finding of an increase in unique names in Japan is robust. These findings were made available online on April 28, 2022, and published on June 21, 2022, in volume 3 of the international journal Current Research in Ecological and Social Psychology.

This study reveals an increase in the rates of unique names in Japan via an analysis of baby names published in municipality newsletters. Unique names increased from at least the 1980s in Japan. It shows that Japanese culture has changed toward greater individualism which emphasizes uniqueness and independence. Therefore, this research contributes to the understanding of changes in not only Japanese names and naming practices but also Japanese culture.

Assistant Professor Ogihara plans to continue investigating the historical changes in names and naming practices in Japan. In the near future, he aims to examine whether these changes have continued in the last few years recently and how COVID-19 has affected naming practices in Japan.


Ogihara, Y. (2021). Direct evidence of the increase in unique names in Japan: The rise of individualism. Current Research in Behavioral Sciences, 2, 100056.

Ogihara, Y., Fujita, H., Tominaga, H., Ishigaki, S., Kashimoto, T., Takahashi, A., Toyohara, K., & Uchida, Y. (2015). Are common names becoming less common? The rise in uniqueness and individualism in Japan. Frontiers in Psychology, 6, 1490.






About The Tokyo University of Science
Tokyo University of Science (TUS) is a well-known and respected university, and the largest science-specialized private research university in Japan, with four campuses in central Tokyo and its suburbs and in Hokkaido. Established in 1881, the university has continually contributed to Japan's development in science through inculcating the love for science in researchers, technicians, and educators.

With a mission of “Creating science and technology for the harmonious development of nature, human beings, and society", TUS has undertaken a wide range of research from basic to applied science. TUS has embraced a multidisciplinary approach to research and undertaken intensive study in some of today's most vital fields. TUS is a meritocracy where the best in science is recognized and nurtured. It is the only private university in Japan that has produced a Nobel Prize winner and the only private university in Asia to produce Nobel Prize winners within the natural sciences field.



About Assistant Professor Yuji Ogihara from Tokyo University of Science
Yuji Ogihara, Ph.D., is an Assistant Professor at the Institute of Arts and Sciences and the Faculty of Science Division II at the Tokyo University of Science in Japan. He earned his doctorate from Kyoto University in 2015. His research interests include cultural change, interpersonal relationships, happiness, individualism, and culture. He has over 30 publications to his name. He is a recipient of numerous awards, including the 2015 Student Poster Award (Society for Personality and Social Psychology) and the 2022 Award for Distinguished Early and Middle Career Contributions (Japanese Psychological Association).


Funding information
This research was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant Number: JP19K14368).

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