April 2021

Mapping POW Camps in Japan during World War II

This set of GIS data layers uses a small sample of historical data to visualize the intersection of war and war crimes across time and space. They reveal information on (1) transportation of prisoners of war from outlying areas in the Pacific theater to the Japanese home islands, (2) locations of Japanese industrial enterprises that used prisoners of war for forced labor, and (3) changing geographical distribution of prisoner-of-war camps in Japan in the last year of the war.

A Guide to Using the Layered Maps

GIS data layers and sources

This digital resource consists of ten GIS data layers. The list of data layers can be seen by clicking the data layer icon at the top left corner of the screen. A data layer gets activated on the map when the corresponding checkbox in the list is clicked. Choosing more than one checkbox allows users to see the selected GIS data layers overlapped.

List of data layers.

List of data layers.

The ten GIS data layers are as follows:

  1. POW camp locations in Japan (U.S. Army intelligence report, 20 Dec 1944)
  2. POW camp locations in Japan (U.S. Army intelligence report, 14 Aug 1945) (a)
  3. POW camp locations in Japan (U.S. Army intelligence report, 14 Aug 1945) (b)
  4. POW camp locations in Japan (mansell.com)
  5. Japanese company locations (powresearch.jp)
  6. Districts of POW camp groups in Japan (powresearch.jp)
  7. POW transport: ports (POW Information Bureau, Japan, 1955)
  8. POW transport: routes & volumes (POW Information Bureau, Japan, 1955)
  9. Industrial concentration by prefectures (OSS map, 21 Aug 1945)
  10. Allied war crimes trials: locations & statistics

The first three data layers draw upon two intelligence reports that the U.S. Army had produced in the last year of the war, dated 20 December 1944 and 14 August 1945, regarding the locations and known strengths of prisoner-of-war camps and civilian internment camps in Japan.1 As the 1945 report includes alternate coordinates for some of the camps, we created two data layers (marked as 1945 (a) and (b) in the data layers list). Comparison of the two intelligence reports reveal significant discrepancies in the camp locations and strengths of prisoners of war. This might have resulted from improvement in the quality of intelligence but it most likely reflects the actual changes in the location and strengths of the prisoner-of-war population in the last months of the war.

The fourth GIS data layer makes use of a dataset on prisoner-of-war camp locations as carried on “Center for Research: Allied POWs under the Japanese,” an online resource center concerning the Allied prisoners of war in Japan during World War II. When activating this particular GIS data layer, users should be aware that this resource center has drawn upon multiple sources to compile a data but that the method of data collection, analysis, or verification is not fully explained.2

The fifth and sixth data layers draw upon a comprehensive list of Japanese industrial enterprises that used prisoners of war in wartime Japan, as compiled by and carried on “POW Research Network Japan,” another online resource center concerning the Allied prisoners of war in Asia and the Pacific during World War II. This map also indicates boundaries between administrative districts in which seven separate prisoner-of-war camp groups were established. Note: The points indicating the locations of companies on the map are clustered together in certain areas, which resulted in the ambiguities of the placement of points in the GIS layer.

The seventh and eighth data layers visualize the data on the routes and volumes of those prisoners of war who were taken from original places of surrender in the outlying areas in the Pacific theater to Japanese home islands for forced labor via transit ports in Southeast Asia, Korea, and the Chinese mainland in 1942-1945, as compiled by the Prisoner-of-War Information Bureau of the Government of Japan in the aftermath of the war.3

“Furyo ikan gaikenhyō” (A birds-eye view of prisoner-of-war transfer).

“Furyo ikan gaikenhyō” (A birds-eye view of prisoner-of-war transfer).

The ninth data layer provides the essential statistical data concerning the trials held by the Allied authorities in Asia and the Pacific.4 The trial of those individuals who were charged with the mistreatment of Allied prisoners of war in wartime Japan were prosecuted at the military commission that the U.S. Army operated at Yokohama, Kanagawa Prefecture, in 1946-1949.

The tenth data layer uses as its source “Japan: industrial concentration by prefectures,” a map drawn from the Office of Strategic Services Maps Collection at the Stanford University Libraries.

POW Camp Groups in Japan

Most prisoner-of-war camps in Japan fell under control of the Ministry of the Army while a handful of prisoner-of-war camps were run by the navy authorities and came within the jurisdiction of the Ministry of the Navy. Similarly, the responsibility of transporting the prisoners-of-war population from the theaters of war to the inner territories of the Empire of Japan fell to the army authorities but there were cases where the navy took upon itself the transport duty with some of the Allied military personnel that it had taken custody during the navy’s air, ground, or naval operations.

For administrative purposes, the army authorities divided the army-run prisoner-of-war camps in Japan into seven “camp groups.” The official name of each camp group carried the name of the prefecture or the prefectural capital city at which the main camp – or the headquarter camp – of the camp group was located. The names of the seven camp groups are as follows: (1) Hakodate, (2) Sendai, (3) Tokyo, (4) Nagoya, (5) Osaka, (6) Hiroshima, and (7) Fukuoka. Each camp group is commonly made up of a main camp and branch camps. Furthermore, two types of ad hoc camps – known as dispatched camps and detached camps – were also created in accordance with work needs.

Locations of POW Camps in Asia and the Pacific

As a pilot project, the geographic scope of data and visualization of this digital resource is limited to Japan proper, but users should be aware that Japan was not the only geographic space in which the Japanese military authorities established prisoner-of-war camps. The camps were set up practically everywhere across the theaters of war in the Asia-Pacific region. The purpose of prisoner-of-war camps was not only to manage the detention of surrendered Allied soldiers but also to use their manpower and to provide logistical support to the Japanese frontline troops. For instance, the prisoner-of-war labor was used for building airfields, anti-aircraft batteries, railways, and other construction work in occupied territories. They were used for sustaining the Japanese arms industries as well, in the inner territories of the Empire of Japan (i.e. Japan, Korea, Manchuria, and Taiwan), such as digging the mines, stevedoring at ports, working at munitions factories, and so on.

The location and the strength of the prisoner-of-war population changed constantly during the war. It was partly because of the frequent death of the prisoners of war resulting from mistreatment and illnesses, and partly because of the needs to shift the detention locations in light of deteriorating circumstances of the war and the corresponding changes in the Japanese military’s logistical priorities. There were cases of mass drowning, too, resulting from the Allied bombing of unmarked Japanese transport ships.

POW Camp Groups and Civilian Internment Camps Outside Japan

Outside Japan proper, the army authorities took formal responsibility for establishing and operating prisoner-of-war camps in Borneo, Burma, China (including Manchuria), Hong Kong, Java, Korea, Malaya, the Philippines, Taiwan, and Thailand. In addition, there are numerous other ad hoc prisoner-of-war camps and prisoner-of-war work parties that the army created in other Japanese-occupied outlying areas – such as the Moluccas, New Guinea, the Bismarck Archipelago, and Solomon Islands – in order to make the prisoner-of-war labor available for various logistical work in support of the frontline troops.5 The navy took custody of some prisoners of war at camps that they separately established and operated in parts of the Central Pacific, such as at Kwajalein and Wake.

Prisoner-of-war camps aside, the Japanese authorities established internment camps throughout the occupied territories, namely, in British Malaya, China, the Dutch East Indies, French Indochina, and the Philippines. In some cases, civilian internees and prisoners of war were kept in the same camp complex. The evidentiary materials admitted at IMTFE regarding the Japanese mistreatment of civilian internees can be located by using the interactive map, Documenting Japanese War Crimes at Tokyo: The International Military Tribunal for the Far East, 1946-1948.

Japanese Companies’ Use of Prisoner-of-War Labor

While the army authorities made arrangements for the transport and accommodation of prisoners of war, the ones who put to use their labor were the owners of mines, dockyards, shipping companies, and other industrial enterprises in Japan and in occupied territories. The organizational dimensions of the Japanese companies’ use of prisoner-of-war labor remain underexplored to this day.

Asian Forced Laborers

The story of wartime forced labor regime of the Empire of Japan would be incomplete if one fails to take into account the presence of a much larger number of Asian people – in the millions – that the Japanese used for forced labor for the duration of the war throughout Asia and the Pacific theater. While comprehensive knowledge of the WWII-era Japanese forced labor regime involving Asians is yet to be attained, the existing historical literature on the matter allows one to learn about its overall scope as well as specific episodes of atrocity.6

Chinese and Korean Forced Laborers

It is known that, in order to make up for an acute labor shortage following the opening of hostilities in the Pacific region, the Japanese cabinet adopted on 27 November 1942, a resolution titled, 「華人労務者内地移入ニ関スル件」 (kajin rōmusha naichi inyū ni kansuru ken) [On the matter of the transfer of Chinese coolies to inner territory], with which to sanction as a matter of formal government policy the mass recruitment, deportation, and employment of Chinese civilians in Japan proper. A postwar investigation by the Japanese Ministry of Foreign Affairs revealed that as many as 38,935 Chinese were sent to Japan for labor over the course of the war in the Pacific, of which 6,830 died by the end of the war. The Japanese military is presumed to have used the Chinese people for forced labor on a much larger scale in the Chinese content but definitive statistical data are not available.

A series of policy decisions were made regarding the use of Koreans for labor by the colonial government and the central government of Japan, since before the start of the war in the Pacific. The data released by Japanese Ministry of Finance showed that as many as 724,871 Koreans were taken to Japan between 1939 and 1945.7 Some of the Japanese companies, especially those who operated mines and construction sites at different locations across the Japanese archipelago, made use of Chinese or Koreans for forced labor as well as the Allied prisoners of war.

  1. “Location and Known Strengths of Prisoner of War Camps and Civilian Assembly Centers in Japan and Japanese-Occupied Territories,” 20 December 1944, Military Intelligence Division, US War Department, Washington, D.C.,” and “Locations and Strength, Prisoner of War and Civilian Internment Camps in Japan,” 14 August 1945, General Headquarters, United States Army Forces, Pacific, MIS – X Section.” These reports are part of the NARA documents (RG 69, SCAP). A photocopy of the reports, which can be found in the Roger Mansell Collection at the Hoover Institution Library and Archives, is used for the present project.
  2. The online resource center in question, www.mansell.com, builds on the Roger Mansell Collection at the Hoover Institution Library & Archives but it indicates that it has also used other sources.
  3. Chaen Yoshio, ed., Furyo jōhōkyoku. Furyo toriatsukai no kiroku [The Prisoner-of-War Information Bureau. The record of the treatment of prisoners of war] (Tokyo: Fuji shuppan, 1992), pp. 228-9. Furyo toriatsukai no kiroku was originally published in 1955.
  4. For the statistical data on the Allied war crimes trials, we mainly referred to Sensō hanzai saiban gaikenhyō 戦争犯罪概見表, which contain summaries of Australian, American, British, Chinese, French, Dutch, and Philippine trials as completed by the Japanese Ministry of Legal Affairs, and which are available at the National Archives of Japan.
  5. The postwar Australian war crimes court at Rabaul dealt with a number of war crimes cases concerning the Japanese mistreatment of Indian and Chinese work parties in the South Pacific.
  6. See Paul H. Kratoska (ed.), Asian Labor in the Wartime Japanese Empire: Unknown Histories (Armonk, New York, and London, England: M.E. Sharpe, 2005).
  7. For more information on Korean forced labor, see Hisako Naitou, “Korean Forced Labor in Japan’s Wartime Empire,” in Asian Labor in the Wartime Japanese Empire (2005), pp. 90-98.