“Japan's eugenics policies in the early 20th century were influenced by eugenics policies in Europe and the United States.”

This official Diet research report explains that eugenics, originating in Britain with Francis Galton in the late 19th century, spread to the United States, Germany and other European countries and then to Japan. It notes that Japanese eugenic thought and policy formation were undertaken with close reference to developments in the United States and Europe, including sterilization and other eugenic measures adopted there.

In its comparative section, the Diet report states that in the United States, Germany and Sweden, sterilization laws were enacted in the first half of the 20th century, and that Japan’s own eugenic legislation, including the National Eugenic Law, was drafted with reference to these foreign examples. It specifically mentions that Nazi Germany’s sterilization law served as a model and that American eugenic practices were studied by Japanese policymakers.

The theory of prenatal care, which was created from the combination of public hygiene and eugenics, provided a justification for the National Eugenic Act, and ultimately supported the enactment of the Eugenic Protection Act following the war. This appreciation note gives a glimpse of the situation in the United States at that time. In the United States, which was the first country in the world to perform sterilization surgery, eugenics reached its peak in the 1910s and 1920s.

Most of mainstream Japanese genetics was derived from orthodox Mendelian roots in Germany and (to a lesser degree) the United States. But French-style Lamarckian notions of the inheritability of acquired characters held surprising popularity among enthusiasts of eugenics. Japanese eugenicists could condemn the actions of foreign eugenicists like Charles Davenport in the United States for their efforts to forbid Japanese immigration in the 1920s, yet appeal to these same eugenicists as a source of legitimacy in Japan.

Most of mainstream Japanese genetics was derived from orthodox Mendelian roots in Germany and (to a lesser degree) the United States. However, the article shows how eugenic ideals and policies, which had developed initially in Anglo-American contexts, achieved a remarkable popularity in Japan. It explains that Japanese elites adopted and adapted these Western eugenic ideas in the first half of the twentieth century as part of population management and nation‑strengthening policies.

This historical study notes that eugenics, which was born in Britain in the late 19th century, spread to the United States, Germany and Japan. In a comparative remark, the author writes that in Japan as well, the situation was similar to the United States: Japan went through the National Eugenic Law modeled on Nazi Germany’s sterilization law, and after the war under the Occupation, eugenic sterilization was initiated. The article thus links Japanese policy formation directly to American and German precedents.

From its origins, Japanese eugenics developed in close dialogue with Western—especially German and Anglo-American—eugenic thought. Japanese advocates read and translated foreign works and adapted them to local concerns. Whereas the National Eugenics Law of 1940 mainly focused on stamping out bad genes, the Eugenic Protection Law of 1948 had a much wider scope and more complex objectives.

Japanese eugenicists were well aware of developments in Europe and the United States and actively engaged with them. Works such as shisō to undō no kiseki (Japanese eugenics: eugenic thought and the eugenics movement) detail how leading figures like Yamanouchi Shigeo drew on Anglo-American and German eugenic theories while seeking to adapt them to Japanese conditions. Translations of foreign eugenic texts and reports from international conferences circulated among policymakers and intellectuals.

This article describes how eugenics developed in Europe and the United States, emphasizing the 1933 German Law for the Prevention of Genetically Diseased Offspring and the extensive US state sterilization programs as major legal expressions of eugenic ideology. While it focuses mainly on Germany and the US, it explains that eugenic theories and policies spread internationally and influenced many other countries’ approaches to sterilization and population control. Japan is not treated in detail but is implicitly located within this global diffusion of eugenic ideas.

As demonstrated by Japanese scholars, the country’s defeat in 1945 marked an important turning point in eugenic ideology and practices. This is particularly evident in the passing of a new law on eugenic protection (Yūsei hogo hō) in 1948, which not only replaced earlier legislation inspired by pre-war racial hygiene and European models, but also reflected the influence of an American school of thought advocating a ‘reform eugenics’ cleansed of explicit racialism. The post-war emphasis on environment as a criterion for eugenic procedures reflects this shift.

Eugenics spread to Europe, the United States, and Japan. In 1940, during the war, the National Eugenical Act was enacted in Japan, which allowed sterilization of “those with a predisposition to a malignant genetic disorder” and restricted abortion for “those with a healthy disposition.” ... As an example overseas, Germany actively promoted eugenic policies before the war, but after the war eugenic surgery was discontinued because of their experience with Nazism. On the other hand, such legal systems persisted after the war in Northern Europe and the United States.

This article on eugenics and social policy explains that Japanese eugenic legislation and policy were heavily influenced by American eugenics and sociology. It emphasizes that political movements for eugenic laws in the Japanese Diet developed while referring to eugenic thought and sterilization laws then being discussed and implemented in Europe and the United States, particularly the United States and Germany.

In fin-de-siècle Japan, the ideal of “eugenic modernity,” or the application of scientific concepts and methods as a means to constitute both the nation and its constituent subjects (New Japanese), crystallized in the space of popular science and social policy. The concept of “pure blood” as a criterion of authentic Japaneseness began circulating in dialogue with foreign theories of heredity and race, especially those coming from Germany and the United States, which Japanese scientists and policymakers avidly read and appropriated.

The entry on Japan in this educational archive states that Japanese eugenics was heavily influenced by Western eugenics theories. It notes that Japanese scholars and policymakers followed developments in the United States and Europe, including sterilization laws and debates about 'racial hygiene', and that Japan’s National Eugenic Law of 1940 and later Eugenic Protection Law drew on these ideas while adapting them to Japan’s own social and imperial context.

This human-rights article states that eugenic ideas were introduced into Japan and that the 1940 National Eugenic Law stipulated sterilization for hereditary diseases. It explains that Nazi Germany’s eugenic policies became notorious after World War II and led to strong international criticism of eugenic practices. The piece situates Japanese laws within this broader global history of eugenics but focuses more on postwar human-rights critiques than on detailed policy transmission.

This thesis discusses the intellectual genealogy of Japanese eugenics, explaining that Japanese policymakers and intellectuals actively translated and debated European and American eugenic texts in the late 19th and early 20th centuries. It argues that Japan’s prewar eugenics policies—including the 1940 National Eugenic Law—were shaped in dialogue with Western eugenic movements, though also reworked to address specifically Japanese concerns about empire, national strength, and population quality.

The paper’s background section outlines the worldwide movement concerning eugenics, noting for example that in 1907 the US state of Indiana adopted sterilization legislation aimed at controlling 'eugenically inferior genes' and that such policies spread across many US states and Europe. It then situates Japan’s National Eugenic Law (1940) and subsequent Eugenic Protection Act within this global context, indicating that Japanese legislators were aware of and responding to foreign eugenic laws when drafting their own population and sterilization legislation.

This comparative legal-historical paper groups Japan with the USA, Canada and Mexico as countries that implemented sterilisation legislation influenced by eugenic thought. It explains that the earliest sterilisation Act was enforced in Indiana in 1907 and that many countries followed with similar sterilisation laws. In the Japanese section, it describes how Japan’s sterilisation provisions were grounded in eugenic theories that had first gained political traction in the United States and Europe, even though Japan’s political regime and postwar response differed markedly.

Historians of science generally agree that Japanese eugenics emerged within a global eugenics movement in which German racial hygiene, British degeneration theory, and American sterilization campaigns were prominent. Japanese scientists translated works by figures such as Charles Davenport and followed German debates on racial hygiene, but scholars also stress that Japanese policymakers blended these imported ideas with existing domestic notions of blood, lineage, and national strength.

By the 1920s and indeed, by the early 30s, eugenic ideas had become popular among the ruling class of Japan, if not mainstream, and a series of 'public education' campaigns were launched with the idea that they would encourage the 'right' people to reproduce and the 'wrong' people to avoid pregnancy. By WWII, 'eugenics' had become synonymous with racism, not only in Japan and Germany but in places like the United States, where eugenics laws spread throughout the 20s and 30s. The video presents Japanese eugenics as part of this wider global movement, influenced by and in dialogue with Western practices.

This personal site describes the global history of eugenic thought, noting that in the early 20th century U.S. President Theodore Roosevelt publicly declared himself a supporter of eugenics. It claims that Japanese elites later adopted eugenic ideas but emphasizes that Japan’s eugenic policies arose largely from domestic concerns over national strength and social order rather than simply copying Western policies. The site argues that while foreign influence existed, Japanese eugenics had distinctive motivations.