Why Did the Japanese Choose War: How to See through the “Pretexts for War” ()
1. Kato Yoko and Her Intellectual Position
The author of the book, Kato Yoko, is a prominent Japanese historian and professor at the University of Tokyo. She has long specialized in the military and diplomatic history of modern Japan, and has consistently taken as her scholarly mission the creation of “a historical image that is neither left-wing nor right-wing, neither based on the logic of banditry nor on a self-tormenting view of history” [1]. Kato’s Why Did the Japanese Choose War was published by Asahi Press in July 2009 and received the Ninth Kobayashi Hideo Prize. Its Chinese translation appeared in September 2019.
2. Why Study the Choice for War
As the author states in her preface, the book was written for the younger generation, primarily young people in Japan. The reason is that Japanese right-wing forces have repeatedly attempted to use ideas and historical narratives associated with past wars to legitimate possible new wars. In this sense, the book is both a work of historical research and a study with a clear concern for contemporary reality [2].
The book’s political background lies in the prolonged and intense debate in Japan between defenders and revisionists of the postwar Constitution of Japan. Viewed from the present, some principles of the Japanese Constitution have, in practice, been altered through legislation and reinterpretation. Among the most important of these changes are those related to transforming Japan into a so-called “normal state.”
In 1945, after Japan’s defeat in the Second World War, a new constitution was drafted under the guidance of the United States and other countries. This constitution was “nothing short of a revolution” for Japan, compelling the country to make a passive commitment that it would “never again wage war.” After revision, the new constitution formally entered into force in 1947 as the Constitution of Japan. Because Article 9 of Chapter II explicitly stipulates that “Japan renounces war as a means of settling international disputes,” it is also known as the “Peace Constitution.” During the Cold War, however, a degree of rightward political thought persisted within Japan, including tendencies to deny acts of aggression and attempts to revive militarism. It can therefore be said that, from the moment the Peace Constitution took effect, debate over constitutional revision has never truly ceased [3].
In 2004, Japan passed the seven emergency-contingency laws, which allowed the Japanese government to deploy the Self-Defense Forces domestically and undertake military action in emergency situations. During the Abe Shinzo administration, the Japanese government not only enacted the National Referendum Law but also adopted, through cabinet decisions, measures such as the security legislation, thereby removing obstacles to constitutional revision or bypassing Article 9’s provisions on renouncing the establishment of armed forces and the right of belligerency. The principle that “Japan may initiate military action only at a time of national crisis threatening its survival” became a new external norm for Japan, and the original constitutional content was circumvented through this mechanism. Under the influence of such political developments, it is of considerable practical significance to re-examine why Japan once chose war, because there is an urgent need to deepen our understanding of whether Japan may once again set war in motion.
From an academic perspective, earlier scholars have in fact already offered extensive discussions of the question of “Why Japan Chose War?” Within Japanese research on the origins of war, Maruyama Masao’s arguments have been especially influential. He maintained that Japan’s path to war was not the accidental act of a single individual or group but was closely connected to structural problems within modern political institutions. Maruyama pointed out that, under the Meiji Constitution, Japan had a cabinet and a parliament, yet the military enjoyed a considerable degree of autonomy in actual political operations, making it difficult for the civilian government to exercise effective restraint. In this system, the emperor was regarded as the supreme authority of the state but did not directly bear political responsibility, while lower-level bureaucrats and the military often acted “in the name of the emperor.” As a result, during major decision-making processes, various departments participated, yet no clearly identifiable final responsible actor existed. Maruyama Masao summarized this condition as an “irresponsible political structure,” arguing that it was precisely under the influence of this structure that Japan gradually slid toward war [4].
Correspondingly, Iriye Akira, beginning from the international environment and diplomatic system, proposed a “systemic collapse” argument. Iriye shifted the focus of analysis to external factors, emphasizing the predicament of “external coercion” that Japan faced under a particular international environment and economic structure. In his view, Japan initially attempted to integrate itself, through international cooperation, into the Versailles-Washington system dominated by Britain and the United States. However, with the outbreak of the Great Depression, the collapse of the international system, and severe economic sanctions imposed on Japan by Britain and the United States, Japan, driven by existential anxiety, ultimately concluded that its survival interests could not be guaranteed within the existing international order and consequently made a “gambling” response in the form of military expansion [5].
Kato Yoko’s research is built upon the achievements of these earlier studies, but it introduces a further innovation in perspective. While previous scholarship has largely focused either on the structural deficiencies of Japan’s domestic political institutions—such as the weakened parliamentary system, the military’s privileged position, and the lack of effective checks on the cabinet—or on the external pressures of the international environment, including the Washington Naval Treaty system, Western colonial policies, and the rise of global fascism, Kato argues that neither approach fully explains how war became acceptable in the eyes of the Japanese public. Rather than focusing solely on the grand narratives of “domestic institutions” or the “international environment,” she seeks to answer a more specific and psychologically grounded question: given the structures and circumstances already in place, how were ordinary Japanese people and elites gradually “persuaded” to make the “choice” for war?
Kato thereby shifts the analytical focus from the question of “who should be held responsible”—a line of inquiry often mired in political and moral debates over war guilt and postwar trials—to the psychological logic of “why people were persuaded.” This reframing moves beyond simply identifying perpetrators and instead examines the mechanisms of consent, the rhetorical strategies that framed war as inevitable or even noble, and the emotional appeals that turned abstract national crises into personal imperatives. In the current historical configuration, compared with previous studies centered on the allocation of responsibility, this deeper perspective grounded in “social psychology” provides a new explanatory path for understanding the mechanisms through which Japanese society accepted war. It illuminates how patriotism was cultivated, how dissent was marginalized, and how a society could collectively embrace a course of action that, in hindsight, proved catastrophic. This approach, therefore, has greater practical value, not only for the study of Japan’s wartime history but also for understanding contemporary phenomena such as the rise of nationalist sentiment, the manipulation of public opinion, and the dynamics of societal mobilization in times of crisis.
With regard to Chinese scholarship on this issue, I would like to cite a passage from Zhang Zhenkun. In my view, it provides an excellent summary of domestic research on “Why Japan Launched War,” while also implicitly demonstrating the significance of Kato Yoko’s book: “Our studies of the history of Japan’s invasion of China have always focused entirely on the actions of its rulers and those in power, rarely touching on the Japanese masses or the majority of the Japanese people. Even when the people are mentioned, they are regarded merely as those who were deceived or coerced, as if Japan’s ruling elites had never received active support from the broad masses for their wanton aggression against China, or as if the invasion of China had no social basis or only an extremely weak one. Is this really the case? Scientific research is needed to answer the question. What position did the Japanese masses, or the majority of the Japanese nation, occupy in modern Japan’s aggression against China? What attitude did they hold? This topic should now be placed on the scholarly agenda” [6].
I therefore argue that Kato Yoko’s research not only adds a new paradigm to studies of the origins of Japanese war, but also provides an illuminating reference for Chinese academia in re-examining the social foundations of Japan’s wars of aggression.
3. The “Line of Interest” and the “Final Choice”: War under Discursive Framing
The book is based on the author’s lectures and exchanges with high-school students and other young audiences. In its mode of narration, it follows chronological development and reviews the background and processes of Japan’s repeated external wars since the modern period.
By “telling events,” Kato Yoko repeatedly guides readers to consider a question that runs through the entire book: at a number of critical historical junctures, why did Japan’s political elites, and even a considerable number of ordinary people, come to regard war as an “acceptable” choice under the circumstances of the time, and even believe it to be an unavoidable outcome? Around this question, the author seeks to avoid simply judging those choices in light of their later consequences. Instead, she attempts to reconstruct the international environment faced by Japanese society when war decisions were made, as well as the anxieties and fears produced by that environment. She ultimately analyzes how “discursive techniques” came to control the public.
From the Paris Peace Conference after the First World War to the oil embargo before the Pacific War, domestic Japanese public opinion repeatedly emphasized Japan’s condition of being “encircled” and “oppressed” by the great powers, a condition that today would be described as a “victim mentality.” This way of thinking was especially evident in the Outline Plan for the Reorganization of Japan by the Japanese fascist thinker Kita Ikki. Through an artificial distortion of Marx’s theory of socialist revolution, Japan positioned itself as a “world proletariat” seeking to “break oppression,” thereby casting a “revolutionary” aura over its acts of aggression. These intellectual currents constituted the psychological background of “seeking security” through which Japanese society continued to move toward war [7].
During the First Sino-Japanese War and the Russo-Japanese War, the main reasons Japan launched war lay in considerations of national border security under the guidance of the “line of interest” idea, as well as in practical calculations within domestic politics. Chapters One and Two analyze the formation of Japan’s strategic outlook during the Meiji period, pointing out that Yamagata Aritomo was deeply influenced by the German scholar Lorenz von Stein’s theory of the state. Japan’s decision-making elite gradually formed the view that merely defending the boundaries of the home islands was insufficient to ensure national security; it was also necessary to control surrounding areas such as the Korean Peninsula as buffer zones, that is, as a so-called “line of interest,” in order to resist the expansion of the great powers [8]. This strategic outlook successfully mobilized domestic public opinion at the time. Under the impetus of nationalist sentiment, even some figures who had originally advocated civil rights and constitutional government came to support external war. In this way, theory and reality, domestic public opinion and international political theory, converged to push Japan toward war.
Although the Russo-Japanese War ended in victory, its costs were extraordinarily high. Japan had mobilized nearly 1.2 million troops and suffered over 80,000 combat deaths, with total casualties exceeding 240,000. The financial burden was equally staggering: the war consumed approximately 1.7 billion yen, roughly four times Japan’s annual government revenue at the time, forcing the government to rely heavily on foreign loans. Yet despite these staggering losses, the fact of victory remained a powerful rallying point for national pride. At this point, the book once again demonstrates the distinctive value of analyzing history through social psychology. The author argues that precisely because victory was achieved only after enormous sacrifice, Japanese society found it psychologically more difficult to deny the meaning of war. To acknowledge that so much blood and treasure had been spent for negligible or even hollow gains would have inflicted an unbearable cognitive dissonance on the public and the ruling elite alike. Instead, the war was elevated to a sacred national enterprise, and its fruits—particularly the rights and interests in Manchuria—were reinterpreted as hard-won achievements that validated the sacrifices of an entire generation. As wartime experience accumulated, these rights and interests gradually acquired a special position in national consciousness and came to be regarded as gains that could not be easily relinquished, let alone negotiated away through diplomacy. This perception, reinforced by patriotic education and media discourse, imperceptibly narrowed the space for subsequent diplomatic and military decision-making. Any proposal for compromise or retreat was now easily branded as a betrayal of the war dead. Thus, the Russo-Japanese War did not simply end; it left behind a psychological legacy that made flexibility in foreign policy increasingly difficult and planted the seeds for Japan’s later adoption of a more hardline stance in external affairs.
In her analysis of the September 18 Incident, the author particularly emphasizes the clear discrepancy between Japan’s military actions and its domestic propaganda. The military’s actual objective in launching the incident was to secure strategic footholds for possible future wars against the Soviet Union and the United States. In explanations directed at domestic society, however, the action was portrayed as legitimate self-defense aimed at protecting Japan’s “vested rights” in Manchuria and Mongolia. This narrative rapidly stimulated support from domestic public opinion and, to a certain extent, obscured China’s response strategy. Citing Hu Shi’s relevant discussion, the book notes that China had envisaged responding to Japanese expansion through long-term attrition [9]. In an atmosphere of constantly intensified patriotism, Japan gradually became trapped in the Chinese battlefield, knowing it was unwise yet unable to extricate itself. The protracted war not only consumed enormous material resources but also deepened domestic political divisions, forcing the military and civilian leadership to double down on an increasingly unsustainable strategy. As the conflict dragged on, rational strategic calculation gave way to a fatalistic mindset. In the final stage of the movement toward total war, Japan’s decision-making elite gradually developed a mentality of “gambling in despair,” or what is now commonly described as “gambling with the fate of the nation.”
Chapter Five, through a detailed analysis of records related to the Imperial Conferences, points out that against the background of the American oil embargo and the gradual formation of the so-called “ABCD encirclement” (American, British, Chinese, Dutch), Japan’s top leadership generally believed that if Japan chose compromise and retreat, the nation would decline as its resources were exhausted; if it chose war, however, it might still have a chance to alter the situation, even though its odds of victory were limited. This binary choice—humiliation and slow decay versus risky but potentially decisive action—framed the strategic debate in purely existential terms. Nagano Osami, Chief of the Naval General Staff, even invoked historical allusions, including the legendary rise of the Mongol Empire and the tactics of Tokugawa Ieyasu, to present war against the United States as a final attempt before Japan was completely constrained. He famously argued that there would be no other opportunity once the oil reserves ran dry. Such judgments, as Chapter Five demonstrates, were already clearly marked by emotional and irrational elements—a blend of national pride, institutional inertia, and sheer desperation—yet they were carefully packaged within a narrative that emphasized Japan’s “victimized situation,” portraying the nation as cornered by Western powers. This self-serving narrative not only justified the decision for war but also successfully influenced the attitudes of many intellectuals, who came to see the Pearl Harbor attack as a tragic but unavoidable act of self-defense rather than an aggressive gamble.
For example, at the outbreak of the war, Takeuchi Yoshimi displayed a complex mentality that viewed the war as an opportunity to break the existing order. Overall, through a carefully sequenced narrative, Kato Yoko shows how Japanese society, in the course of continually pursuing “security,” made a series of choices that appeared reasonable at the time but ultimately produced grave consequences.
In terms of research methodology, whereas many existing studies have been grounded in the single disciplinary frameworks of political history or intellectual history, the author comprehensively employs methods from history, political science, international relations, and cultural psychology. In doing so, she gradually clarifies the deeper causes that repeatedly led modern Japan toward war and lays a solid theoretical foundation for an integrated discussion of this issue [10].