When words signal conflict: Measuring exclusionary nationalism in prewar Japan
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Why do countries go to war? While economic, military and geopolitical factors are often part of the answer, researchers have also pointed to exclusionary nationalism—the belief that one's own nation is superior to others. One observable trace of such sentiment is language: As exclusionary attitudes intensify, people tend to favor words from their own language over foreign ones and even reject the "enemy's" words outright.
History offers many examples, from the renaming of German-derived words in Britain during the First World War to recent restrictions on Russian-language print media in Ukraine. This pattern suggests that tracking the acceptance or rejection of foreign loanwords could serve as a window into exclusionary nationalism across countries and eras.
Japan's writing system offers a test
Prewar Japan offers an especially advantageous case for testing this idea because the Japanese writing system makes it easy to tell foreign loanwords apart from native words. Japanese is written with three sets of characters: Foreign-language words are usually transcribed in katakana, whereas traditional Japanese words use hiragana and kanji. For a foreign place name, writers could therefore choose either a katakana loanword or a kanji-based transliteration known as ateji.
This built-in choice gives researchers a clear linguistic signal with which to observe shifting attitudes toward both allies and enemies before and after Japan entered the war in December 1941. The years leading up to the war were marked by several political events associated with rising nationalist sentiment in Japan.
These included coup attempts by members of the Japanese military in 1932 and 1936, Japan's withdrawal from the League of Nations in 1933, the enactment of the National Mobilization Law in 1938 and the signing of the Tripartite Pact with Germany and Italy in 1940.
Turning language into a measure
Given that exclusionary nationalism can either contribute to war or emerge in response to it, Associate Professor Tomoko Matsumoto from the Institute of Arts and Sciences at Tokyo University of Science (TUS), Japan; Visiting Associate Professor Yutaka Shimada of TUS and Saitama University, Japan; and former student Hiroyuki Hirate and Professor Tohru Ikeguchi, both from TUS, wondered whether shifts in nationalism could be traced through changes in language use.
They developed a statistical approach to track changes associated with exclusionary nationalism in newspapers and examine how these changes evolved before and after Japan entered the war in 1941.
Their findings, published in the journal PLOS One, suggest that changes in how foreign place names were written may reveal shifting attitudes toward foreign countries.
"This method makes it possible to quantitatively grasp the time-series changes in nationalism and perceptions of foreign countries from linguistic data, such as newspapers and social media, even in eras and regions where public opinion polls do not exist. Therefore, it is expected to be applicable to the early detection of international conflicts and social divisions in modern society," says project team member Matsumoto.
Signals shifted with political events
To track the emergence of exclusionary nationalism, the researchers analyzed how foreign place names were written in 300,110 newspaper articles published by 54 Japanese newspapers between 1912 and 1943.
The Japanese language commonly uses katakana to phonetically represent foreign words, but foreign locations can also be written using kanji-based transliterations known as ateji. The researchers hypothesized that shifting away from foreign-sounding katakana and toward ateji could reflect growing exclusionary attitudes toward foreign countries.
Using a statistical method called singular spectrum transformation, the team tracked month-by-month changes in the use of ateji and katakana for foreign place names, focusing on the United States and the United Kingdom, which later became Japan's enemies, and Germany and Italy, which became allies.
The findings revealed that exclusionary nationalism in Japan did not steadily rise before the Pacific War but fluctuated over time. The researchers identified notable turning points in 1924, 1927, 1936 and 1938 that coincided with key political events.
The use of katakana increased after 1924, coinciding with the appointment of Foreign Minister Kijūrō Shidehara, who promoted international cooperation. However, this trend slowed after his resignation in 1927 and shifted further following the February 26 coup attempt in 1936, a period associated with growing militarization.
Notably, katakana remained more common for German and Italian place names, highlighting differences in how Japan viewed future allies and enemies long before the war began.
Language patterns may flag tensions
In a world increasingly shaped by geopolitical tensions, understanding the forces that drive conflict is more important than ever. The researchers suggest that their method could help detect early signs of international conflict and social division by analyzing patterns in language use.
"This study deepens our understanding of the role of exclusionary nationalism in conflicts, highlighting its nuanced nature in shaping friend-enemy distinctions during wartime," note the researchers.
Publication details
Tomoko Matsumoto et al, Identifying surge of exclusionary nationalism: A case study of prewar Japan, PLOS One (2026). DOI: 10.1371/journal.pone.0349895
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Citation: When words signal conflict: Measuring exclusionary nationalism in prewar Japan (2026, July 14) retrieved 17 July 2026 from https://phys.org/news/2026-07-words-conflict-exclusionary-nationalism-prewar.html
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