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Japan’s Forgotten Korean Forced Laborers: The Search for Hidden Wartime Graves in Hokkaido

Published online by Cambridge University Press:  02 April 2024

Ágota Duró
Faculty of Humanities Department of International English, Hiroshima Jogakuin University, Hiroshima, Japan
David Palmer*
School of Historical and Philosophical Studies, The University of Melbourne, Melbourne, VIC, Australia
Corresponding author: David Palmer; Email:


The return of remains of Korean forced laborers who died in Japan between 1940 and 1945 has been a major controversy for over half a century for Koreans. These deaths reveal the tragic consequences of Japan’s World War II forced labor system. Japan forcefully mobilized nearly 800,000 Koreans who were taken to at least 1,589 worksites in Japan and 381 worksites in Hokkaido. Over 10 percent of all Koreans forcefully mobilized throughout the empire are estimated to have died or disappeared, but the precise number of Korean forced laborers’ deaths inside Japan remains unknown. Until 1989, remains recovered from graves throughout Japan by local people were immediately cremated by Japanese Buddhist priests, making cause of death and precise identities forensically impossible. This account relates the first and only comprehensive effort to exhume Korean forced labor graves without immediate cremation, coordinated by Korean and Japanese activists and academics based in Hokkaido. This effort helped revive a neglected aspect of Korean forced labor history while focusing on the concerns of bereaved Koreans seeking the remains of their lost family members. Nevertheless, the project had serious limitations due to working in a difficult political environment and neglect of forensic science protocols in mass grave excavations and identification. This complex situation prevented identification of victims’ names and cause of death that could have held the Japanese government and companies involved accountable.

© The Author(s), 2024. Published by Cambridge University Press on behalf of International Labor and Working-Class History, Inc.

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This article has been updated since original publication.



1. Fukagawa Munetoshi, Chinkon no Kaikyō—Umi ni Kieta Hibaku Chōsenjin—(Straits of Dead Souls: The Korean Atomic Bomb Survivors Who Vanished at Sea) (Akashi Shoten, 1992originally published 1974); Ágota Duró, “Confronting Colonial Legacies: The Historical Significance of Japanese Grassroots Cooperation for the Support of Korean Atomic Bomb Survivors,” (Ph.D. dissertation, Hiroshima City University, Hiroshima, 2017), 217–43; David Palmer, “The Straits of Dead Souls: One Man’s Investigation into the Disappearance of Mitsubishi Hiroshima’s Korean Forced Labourers,” Japanese Studies 26, no. 3 (December 2006): 335–52.

2. Commission on Verification and Support for the Victims of Forced Mobilization under Japanese Colonialism in Korea, Final Report of the Commission’s Activities (Republic of Korea, June 2016), 38–55. The Commission’s 10 percent overall figure for deaths and missing includes Korean “soldiers, civilian workers in the military, laborers, and comfort women” as well as imprisoned victims who “refused to be drafted or who died in the mobilization process,” so this percentage encompasses all of Japan’s wartime occupied territories, not just Japan proper.

3. Takeuchi Yasuto, Senji Chōsenjin Kyōsei Rōdō Chōsa Shiryōshū (Wartime Korean Forced Labor Research Documents) (Kobe Student Youth Center, 2022), 242. These figures do not include deaths at sea offshore Hokkaido or Sakhalin, Okinawa, and other locations beyond the main islands of Japan.

4. For Korean workers in the interwar period, especially the 1920s, and the “contingent labor” argument, see Ken C. Kawashima, The Proletarian Gamble: Korean Workers in Interwar Japan (Durham: Duke University Press, 2009).

5. Jerome B. Cohen, Japan’s Economy in War and Reconstruction (Minneapolis: University of Minnesota Press, 1949), 300, 301; David Palmer, “Japan’s World Heritage Miike Coal MineWhere prisoners-of-war worked ‘like slaves,’” The Asia Pacific Journal/Japan Focus 19, no. 13 (July 1, 2021): 5605; Commission, 51, 52; Takeuchi, Senji Chōsenjin, 18. By the middle of World War II, the Japanese government sent skilled workers overseas, leaving a serious skills deficit even as forced laborers took their place, along with high school students and women without skills. The national distribution of employment in Japan’s coal mines further reflects this. By March 1945, there were 412,241 employees in coal mines: 265,776 Japanese full and part time; 135,751 Koreans; 9,651 Chinese (all forced laborers); and 7,362 Allied POWs. The deteriorating conditions in Japanese industry, including the deadly coal mines where physical labor dominated over mechanized mining, would most likely have led to Korean death rates of 10 percent or higher. The disparity between the Commission’s worksite numbers and Takeuchi’s company numbers for Hokkaido is a problem that requires further documentary investigation. Takeuchi’s company data in general appears to be more comprehensive than the Commission’s. For total number of companies in Japan using Korean forced laborers, Takeuchi lists 2,926 with company names, while the Commission Final Report lists 2,876 but without company names.

6. Supreme Court of Korea, 1st Division Judgment, “Case no. 2009 Da 22549, Issued May 24, 2012” (unnamed plaintiffs v Mitsubishi Heavy Industries), Korea Journal of International and Comparative Law 2 (2014): 214. Nippon Steel (found liable in a parallel lawsuit) and Mitsubishi Heavy Industries appealed the 2012 decisions. In 2018, the South Korean Supreme Court denied the appeals and ordered both companies to pay compensation to the plaintiffs and threatened seizure of the companies’ assets in South Korea if they refused to comply. For background on the 2012 Mitsubishi Hiroshima Shipyard case involving Korean workers, see David Palmer, “Foreign Forced Labor at Mitsubishi’s Nagasaki and Hiroshima Shipyards: Big Business, Militarized Government, and the Absence of Shipbuilding Workers’ Wights in World War II Japan,” in On Coerced Labour: Work and Compulsion after Chattel Slavery, eds. Marcel van der Linden and Magaly Rodriguez Garcia (Leiden: Brill, 2016), 159–84. For legal and political events from 2018 to 2023, see Sven Saaler, Hideko Yano, and Yeong-Hwan Kim, “Japanese and Korean Perspectives on the Issue of Forced Labor in the Asia-Pacific War,” The Asia Pacific Journal / Japan Focus 21, no. 10 (October 17, 2003), 5799.

7. See, for example, Takeuchi Yasuto, Chōsa: Chōsenjin Kyōsei RōdōTankō Hen (Investigation: Korean Forced LaborCoal Mine Volume) (Tokyo: Shakai hyōronsha, 2013).

8. Palmer, “Foreign Forced Labor at Mitusbishi’s Shipyards,” 171, 172; Cohen, Japan’s Economy, 271–326.

9. For forensic anthropology and scientific excavations of graves internationally, see Angi M. Christensen and Nicholas V. Passalacqua, A Laboratory Manual for Forensic Anthropology (London: Academic Press, 2018); and Layla Renshaw, Exhuming Loss: Memory, Materiality and Mass Graves of the Spanish Civil War (Walnut Creek, CA: Left Coast Press, 2011).

10. Tonohira Yoshihiko interview with Palmer, online, May 9, 2021.

11. Gil-Soo Han, Funeral Rites in Contemporary Korea: The Business of Death (Singapore: Springer Nature, 2019), 179; Chang-Won Park, “Funerary Transformations in Contemporary South Korea,” Mortality 15, no. 1 (February 2010): 21–3; Ri-Hye Han, “Graveyard Geomancy in Korea under Japanese Rule – Focusing on the 1930s,” Contemporary Japan 32, no. 1 (2020): 25–42; Mark E. Caprio, Japanese Assimilation Policies in Colonial Korea: 1910–1945 (Seattle: University of Washington Press), 141–70.

12. Tessa Morris-Suzuki, “Letters to the Dead: Grassroots Historical Dialogue in East Asia’s Borderlands,” in East Asia Beyond the History Wars: Confronting the Ghosts of Violence, ed. Morris-Suzuki, et al. (London: Routledge, 2013), 87–103; Yeong-Hwan Kim, “Promoting Peace and Reconciliation as a Citizen of East Asia: The Collaborative East Asian Workshop and the Grassroots House Peace Museum,” The Asia-Pacific Journal/Japan Focus 5, no. 12 (December 1, 2007).

13. Duró, “Confronting Colonial Legacies,” 217–243; authors’ email exchanges with Tonohira regarding Japanese Buddhist cremation standards for temples.

14. Tonohira Yoshihiko, Ikotsu―Katarikakeru Inochi no Konseki (Remains: Traces of Life that Speak to Us) (Kyoto: Kamogawa Shuppan, 2013), 47; Tonohira interview with Palmer; David Plath, So Long Asleep: Waking the Ghosts of a War (Massachusetts: Documentary Educational Resources, 2016) (video documentary).

15. Sorachi Minshūshi Kōza Henshū, Wakai no Kakehashi: Shumarinai, Kankoku, Minshū (Bridge of Reconciliation: Shumarinai, Korea, and the People), (Asahikawa, Hokkaido: Sorachi Minshūshi Kōza, 1994), 16–17; Tonohira Yoshihiko, Wakamonotachi no Higashi Ajia Sengen: Shumarinai ni Tsudou Nichi, Kan, Zainichi, Ainu (Young People’s East Asian Declaration: Japanese, Korean, Zainichi, Ainu Meet in Shumarinai) (Kyoto: Kamogawa Shuppan, 2004), 29; Plath, So Long Asleep.

16. Kikkawa Tetsunin, “Shirizu: Rekishi no Shinjitsu e – Hokkaido (Shumarinai), Kōbo, soshite Nikkan kōryū, ikotsu hōkan undō” (Without knowing: Toward the Historical Truth – Hokkaido (Shumarinai), Kōbo, and Japan-Korea Exchange, Return-of-remains Movement), Kyūjō no Kai Hatsukaichi Kaihō no. 57, (October 1): 2018; Tonohira, Wakamonotachi, 23–5; Takeuchi, Senji Chōsenjin, 74; John G. Roberts, Mitsui: Three Centuries of Japanese Business (New York: Weatherhill, 1974), 341–64; Ahn Michimasa, “Ikotsu to tsuitō: Hokkaido Shumarinai ni okeru Ikotsu Hakkutsu Undō o Jirei toshite,” (Remains and Mourning: The Movement to Excavate Remains in Shumarinai), Japan Oral History Association no 3 (September 2009), 141; Cohen, Japan’s Economy.

17. Tonohira, Wakamonotachi, 29–32, 110; Plath, So Long Asleep.

18. Ahn, “Ikotsu to tsuitō,” 141, 33–4; Yamaori Tetsuo, Wandering Spirits and Temporary Corpses: Studies in the History of Japanese Religious Tradition (Kyoto: International Research Center for Japanese Studies, 2004); Plath, So Long Asleep.

19. Sorachi Minshūshi Kōza Henshū, Wakai no Kakehashi, 76–7; Tonohira email to Duró, Nov. 5, 2021; Ahn, “Ikotsu to tsuitō,” 125–44.

20. Plath, So Long Asleep.

21. Ibid.

22. Kikkawa, “Shirizu.”

23. Chung Byung-Ho, “Gieoggwa chumoui gong-gong-inlyuhag: ilje gangjenodong huisaengja balgulgwa gwihwan (Public Anthropology of Memory and Remembrance: Discovering and returning forced labor victims from the Japanese occupation),” Research Papers, Korean Cultural Anthropology 1, no. 50 (March 2017): 7–9.(Korean translation: assistance Nikolai Johnsen); Tonohira, Wakamonotachi, 72, 126; Anonymous academic participant email correspondence with Palmer.

24. Chung Byung-Ho, “Coming Home after 70 Years: Repatriation of Korean Forced Laborers from Japan and Reconciliation in East Asia,” The Asia-Pacific Journal / Japan Focus 15, no. 35 (June 15): 2017.

25. Plath, So Long Asleep; Chung, “Gieoggwa”; Chung Byung-Ho interview with Duró, Shumarinai, Hokkaido, August 19, 2023.

26. Song Ki-Chan interview with Duró, March 26, 2021; Sakashita Atsushi, “Hokkaidō Shumarinai no Ikotsu Hakkutsu Henkan Undō” (Movement to Excavate and Return Human Remains in Shumarinai, Hokkaido) (Master’s thesis, Sapporo University, Sapporo, 2005), 17.

27. Tonohira, Wakamonotachi, 38.

28. Chung, “Gieoggwa.”

29. Physical anthropology is concerned with the study of human biological and physicological characteristics and development but forensic anthropology (considered a subfield of physical anthropology) is the more specialized systematic study of skeletal or fragmentary remains to create a biological profile of the deceased requiring training in exhumations and scientific laboratory analysis.

30. Chung, “Coming Home after 70 Years.”

31. Plath, So Long Asleep.

32. Tonohira, Wakamonotachi, 12-13. Matsumura Hirofumi, “Horokanai-chō shumarinai yori shutsudo shita jinkotsu” (Human Bones Excavated from Shumarinai, Horokanai Town), medical report, Sapporo Medical University, 2003; Sakashita, “Hokkaidō Shumarinai,” 24–25.

33. Tonohira, Ikotsu, 23; Takeuchi, Senji Chōsenjin, 154, 155, lists 91 Korean deaths at Asajino.

34. Tonohira, Ikotsu, 23–8. Tenpoku Shimbun (天北新聞) was a local newspaper in Sōya (宗谷) Subprefecture in the 1970s.

35. Hokkaido Forum, in Sapporo, functioned independently from Chung’s East Asian Cooperative Workshop. It was involved in consultations with Japanese and South Korean government-affiliated representatives in trying to resolve the “return-of-remains” issues. Kim Min-Young, Hoskaido (baehaedo) saspolo byeol-won sojang yugoljosa (Investigation into Remains held by Hokkaido Sapporo Betsuin Temple Annex), Japanese Forced Mobilization Victims Support Foundation, Dec. 2017; Chung, “Gieoggwa.”

36. Tonohira’s book Ikotsu (2013) gives a similar number but without any description of the remains being cremated or skeletal. When we questioned Tonohira as well as participants involved in the Asajino excavations, they gave differing answers on how many remains were skeletal. Chung’s article in Korean incorrectly states that 38 Korean remains were found at Asajino. These conflicting numbers and the absence of accurate published data is indicative of poor record keeping by the Workshop leaders.

37. Tonohira, Ikotsu, 29–39.

38. Higashi Ajia Wakushoppu 2015 in Kansai (East Asia Workshop 2015 in Kansai) 6-9 (program guide provided by Song Ki-Chan); Takeuchi, Senji Chōsenjin, 15–18, 74, 75, 122–61; Chung interview, August 19, 2023.

39. Song interview; “Higashikawa de Kyōdō Wakushoppu—Kyōseirenkō Giseisha no Ikotsu Hakkutsu—Tsuitō Kai” (Higashikawa Cooperative Workshop—Excavation of Korean forced labor victims’ remains—Mourning Association), Weekly Ashikawa Shimbun Online, August 6, 2013 For the schedule and plan for the excavation, see accessed March 6, 2023,

40. Plath, So Long Asleep.

41. For a detailed account of these government-to-government consultations and the inability of the South Korean Commission to move forward with Japanese government representatives by 2012, see Kim Min-Young, Hoskaido. Between 2008 and 2010, 423 “ash boxes” were returned to South Korea but these were all “forcibly mobilized as soldiers or civilian workers in the military” rather than Korean forced laborers in Japan. Every reference to “remains” in the Commission summary report refers to “ash boxes,” but none to excavations of graves in Japan or the problem of cremation destroying evidence for DNA or forensic analysis (Commission, 92, 93).

42. Takeuchi, Senji Chōsenjin, 74, 153, 154; Tonohira Yoshihiko, Uryū Dam Korean deaths, handwritten list, April 2021.

43. Tonohira, Ikotsu, 205–206; Kim Min-Young, Hoskaido; Honganji Sapporo Betsuin Ikotsu Chōsa Iinkai (Honganji Sapporo Betsuin Temple Remains Investigation Committee), “Honganji Sapporo Betsuin ni okeru ikotsu mondai hōsa Hōkokusho, ‘Jōkeshū Nōkotsudō’ to ‘Chizaki Kōgyō Nōkotsudō’” (Investigation Report Concerning the Remains Problem: “Jōkeshū Ossuary” and “Chizaki Company Ossuary”), November 30, 2003.

44. Tonohira, Ikotsu, 209, 214; Kim Min-Young, Hoskaido.

45. Kim Min-Young, Hoskaido.

46. Tonohira, Ikotsu, 204-208; Kim Min-Young, Hoskaido.

47. Tonohira, Ikotsu, 209, 210.

48. Ikotsu Hōkan: 70 Nenburi no satogaeri (Honorable Return of Remains after 70 Years), “Homecoming” pamphlet in Japanese, 2015, from Tonohira; Song interview; Kim Min-Young, Hoskaido.

49. See for example Morris-Suzuki, “Long Journey Home”; William Underwood, “Names, Bones, and Unpaid Wages (1),” The Asia-Pacific Journal / Japan Focus 4 (September 2006): 2219 [original title of this publication].

50. Plath, So Long Asleep.

51. Sohn Sung-Hyun, “70 Year Homecoming: Displaced Souls, Displaced People,” online exhibit: accessed March 6, 2023,

52. Photos taken by Sohn Sung-Hyun in Osaka at the Jōdo Shinshū temple during the September 2015 journey from Hokkaido to Seoul. Sohn message with photos to Palmer, March 11, 2022.