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Law without Mercy: Japanese Courts-Martial and Military Courts During the Asia-Pacific War, 1937-45


Fachbereich Geschichts- und Kulturwissenschaften
Ostasiatisches Seminar


European Research Council

01.10.2019 — 30.09.2025


ERC Consolidator Grant Project (ERC-2018-COG 819892)

Law Without Mercy: Japanese Courts-Martial and Military Courts During the Asia-Pacific War, 1937-45

I. Project Summary

Japan fought the war over East and Southeast Asia between 1937 and 1945 not only in the theatres of war, but with equal harshness in the courtrooms of military justice. Wherever Japanese soldiers went, judge-advocates followed, meeting out stern justice to soldiers, civilians and enemy soldiers alike. The system of courts-martial and military courts throughout East and Southeast Asia served three purposes: regulate violence and channel it efficiently to serve Japan’s war goals; deter the civilian population and coerce it into following Japan’s ‘New Order’ in East Asia; and finally, convince domestic and international audiences that Japan’s war was not only legitimate, but also ‘legal’. Yet, despite formal pretences, verdicts of civilians routinely ended in execution or harsh imprisonment. As such, the violence of the justice system mirrored the brutality of the war in general.

Despite the highly contentious nature of the war even today, a systematic studies of mass violence during the Asia-Pacific War are sorely lacking. ‘Law without Mercy’ uses military justice as focal point and as a highly precise lens for studying the various figurations of violence during the war. It is pioneering in analysing legal practices as an integral part of this violence and facilitator for its routinisation and escalation on the battlefield and in the occupied territories. And finally, it opens up a wholly new and large body of sources (primarily court judgments and briefs, but also memoirs, reports, policy papers etc.) that helps to overcome the notorious direness of documentation on Japan’s conduct during the war.

The project’s principal aim is to advance our historical understanding of the inherent reasons and mechanisms of mass violence during the Asia-Pacific War and the role that law played in it. However, the complex and precarious relation between law, war and violence is still at the heart of humanitarian issues today. Thus, the historical insights of this project also have very practical implications for our conflict-laden world today.


II. Extended Synopsis

1. Research Problem

When Japan expanded its empire on the Asian continent and entered all-out-war with China in 1937 and the US in 1941, it waged war as much on the ideational as on the physical level. The courts-martial and military court system that Japan established throughout East and Southeast Asia were but different theatres of war that served crucial functions in Japan’s ‘war without mercy’ (Dower 1986). On the formal level, adjudication of soldiers and civilians sought to demonstrate to audiences at home and abroad that Japan was fighting a ‘lawful’ war that observed the laws in war to the letter and legitimately liberated Asia. In substance, however, it served Japan’s total war goals through punishment and deterrence, remoulding soldiers into more efficient fighting machines and cowing civilians into submission to Japan’s ‘New Order’ in East Asia. However, contrary to expectation, this often led to an escalation rather than containment of violence.

‘Law without Mercy’ examines the Japanese military justice system as an institution at the interface of violence, law, and ideology, providing unique and novel insights into the dynamics of the Asia-Pacific War. In particular, it contributes to solving some of the most challenging issues of the Asia-Pacific War, namely the causes of the horrendous escalation of mass violence (defined as widespread and excessive use of force outside actual fighting) and the ambivalent role that law and legal practice played in it. Although not unique to the Asia-Pacific War (and thus findings of the project are relatable to other cases and the general debate), the gap between the legal and ideological level and the horrendous physical reality of the war has been particularly wide and difficult to explain in the case of Japan’s war conduct. ‘Law without Mercy’ postulates that far from contradicting each other, violence, law and ideology were in fact mutually dependent and reinforced each other. In these dynamics, law played a key role as mediator of violence and ideology.

Thus, when Japan entered the war with China in 1937, both parties refrained from declaring war for strategic and ideological reasons. Japanese authorities, however, stated that they would apply the laws of war nonetheless to the letter (Zachmann 2013). Japan reaffirmed this adherence when it entered war with the US in 1941. Moreover, its expansion on the continent and into the Pacific was accompanied by the highly utopian rhetoric of a ‘New Order’ and ‘Co-Prosperity Sphere’ in East and Southeast Asia. Japanese experts were even drafted into the project of devising a legal blueprint for an ‘East Asian international law’. And yet, the brutal realities belied official statements. Violence perpetrated against civilians was pervasive, as was insubordination of soldiers within the military. Civilians in the occupied territories responded with violence, either individually or as part of guerrilla warfare. Thus, courts-martial and military courts were swamped with an ever-increasing number of cases.

The military justice system generally mirrored, and substantially contributed to the escalation of violence of the Asia-Pacific War: Courts-martial prosecuted Japanese soldiers for military offences, including insubordination against superiors and crimes against civilians. Military courts prosecuted civilians in occupied territories for criminal offences and violations of criminal provisions. There were considerable variations in the way the system was set up: In some areas, local judges and the police were coerced or co-opted into the proceedings, which raises sensitive issues of collaboration and the role of local elites. In most cases, however, the Japanese military took adjudication upon itself. Moreover, military courts also dealt with ‘grave war crimes’ of soldiers of enemy countries.

Trials reproduced the irritating disconnect between excessive attention to form on the outside and extreme brutality in substance: Cases were often meticulously documented, minutely detailing the personal history of defendants as well as the facts underlying the accusations. Thus, the case files prepared by the military legal services provide a wealth of information and offer a fascinating insight into the situation of soldiers at the front and civilians in the occupied territories. Yet, trials were held in swift manner, with no right to appeal or petition and with predictable outcomes: ninety per cent of civilians were executed; soldiers were imprisoned and re-educated, only to be dispatched swiftly back to the frontline.

Yet, there was also palpable tension within the courts, as these were regularly composed of military and formerly civilian members (the legal experts). Thus, through memoirs and notes, we also get a brief glimpse into the intense ideological struggles that played out between these constituencies, thus mirroring the tensions of the Japanese empire and the course of war in nuce.

‘Law without Mercy’ analyses the verdicts, investigation reports, personal notes and ministerial documents related to military justice as a way to shed light on law’s role in the escalation of violence during the Asia-Pacific War. By systematically analysing a whole new body of sources in a unique and novel conceptual framework, this study is pioneering an innovative and productive line of historiographical inquiry. This project provides insights into the relation of law and violence in war that are still central to many humanitarian issues in our world today.

2. Research Aims and Objectives

The primary aim of ‘Law without Mercy’ is to trace the following interrelated dynamics of the Japanese wartime empire during the Asia-Pacific War through the lens of Japan’s military justice system and situate them within the wider context of the history of violence in modern Japan, legal history, intellectual and political history:

  1. The dramatic escalation of mass violence, particularly the deterioration, as reflected in military court cases, of military discipline and violation of military standards in many theatres of the Asia-Pacific War, and the concomitant gross violations of rights of civilians in occupied territories;
  2. The increasingly strategic subordination of law to the agenda of Japan’s ‘Greater East Asian War’, using law as a bureaucratic tool of rationalisation and standardisation, as a means to indoctrinate and intimidate soldiers and civilians in the service of total war, but also – perhaps – in some cases as a ground to contest and subvert this agenda;
  3. The intense ideological struggle over Japan’s war aims and the ultimate power to define the nature of the war that interfered with and informed the adjudication of courts-martial and military courts in the Asia-Pacific War.

The central purpose of this project is to advance research on Japan’s war history through making accessible a whole new body of historical sources for analysis and raise questions that provide new insights into the nature of Japan’s war conduct and belligerent occupation. Providing new qualitative data to the public, it informs historical debates on Japan’s war conduct as well as the relation of law and belligerent violence in general.