The Migration, Mobilization, Working Environment, and Daily Lives of Korean Laborers at the Sado Mines, 1940-1945: A Critique of the “Forced Mobilization” and “Forced Labor” Arguments

Lee Woo-yeon (Naksungdae Institute of Economic Research Committee member)


The Migration, Mobilization, Working Environment, and Daily Lives of Korean Laborers at the Sado Mines, 1940-1945: A Critique of the “Forced Mobilization” and “Forced Labor” Arguments


  1. How was the Korean Wartime Mobilization Carried Out?

South Korean and Japanese media reports and previous studies on Korean migration and mobilization to the Sado mines during the war have all been mere recapitulations of the sentiments expressed in Record of the Forced Mobilization of Koreans, published in 1965 by a non-professional, self-proclaimed “expert” researcher. The author was a teacher at the Chongryon’s Korea University who made no attempt to hide the fact that his purpose in publishing it was to prevent the restoration of diplomatic relations between South Korea and Japan. He argued that the process by which Koreans were brought to Japan was “slavery”-that is, “forced mobilization”-and that in Japan, they were used in “slave labor”, or “forced labor”.

Koreans were mobilized across three stages: “recruitment”, “official mediation”, and “conscription”. Recruitment was precisely that; company representatives traveled to Korea, where it was public knowledge among farmers that they had come to hire employees. “Official mediation” differed from recruitment only in that the local police voluntarily provided administrative support to recruiters dispatched from Japan, while “conscription” was legally enforced (those who did not comply faced up to one year in prison and a fine of up to \1,000 JPY. To put this into perspective, the wholesale price of rice in Seoul between 1939-45 was \38-47 JPY per 1.8kg, according to the Historical Statistics of Korea Vol.2, p.822, 2018, edited by Kim Nak-nyeon, Park Ki-joo, Park Lee-taek, and Cha Myung-su). However, conscription also entailed a lengthy series of legal procedures that took approximately an entire month; first, a summons was issued to conscripts. Once they received this, they were then obliged to take a medical examination, after which-if they were deemed medically fit-they finally reported for duty at the designated place and time. Accounts from those who claim to have been whisked away “while sleeping at home”, “while working in the fields”, or “forcibly mobilized” do not comport with the facts. This misconception is believed to stem from the conflation of the “street recruitment” that took place during the Korean War (coercive enlistment in front of schools, in homes, and on the streets without an official summons) with the wartime mobilization under colonial occupation.


Unlike the “recruitment” that took place from September 1939, the mobilization of Koreans under “official mediation” from February 1942 was based on a 1940 “Labor Resources Survey” by the Government-General of Korea. How the Korean authorities dealt with the mobilization during this phase varied significantly, which manifested in an equally varied degree of “coercion”. The reason for this is that there was no law stipulating the methods by which Koreans were to be mobilized or any punishment for those who failed to comply; labor division personnel from Japanese companies, the Government-general of Korea, and the local police simply disseminated public information administratively to young Korean men and solicited or coaxed them into applying.


  1. A Case Study of Sado: Concerning wages

Even before the initiation of the Japanese government’s wartime labor mobilization in September 1939 and the Sado mines’ subsequent recruitment of Koreans in line with this policy in February 1940, migrant Korean workers who had come to Japan to earn money were already employed at the mines. These more experienced workers would have served in the capacity of mentors and directors for the wartime laborers. In a broad sense, from the perspective of the corporate sector, mobilization was a means of addressing labor shortages (although the Japanese government’s perspective may differ), while for Koreans, it was characterized by the movement of labor outside the Korean Peninsula or emigration. Considered in this light, the nature of the wartime migration of Koreans to Japan is contiguous with that of post-liberation migration.

As with other establishments, Korean workers at the Sado mines, including those recruited under conscription from September 1944, were paid wages on a regular basis. For both Koreans and Japanese, compulsory savings, labor income tax, health insurance premiums, and pension insurance were deducted from their salaries. With the exception of savings, these deductions were not so large, and Koreans were free to decide whether to send the money to their families in Korea or spend it locally. The most notable discrepancy between the Japanese and Koreans in terms of deductions was the compulsory savings, but this was because, unlike Japanese workers, many Koreans were single workers with no families, and they had a much greater capacity to save than Japanese with families to support.

A comparison of the amount of money that the Sado mines did not-or could not-pay Koreans which was deposited with the Legal Affairs Bureau (an average of \203 JPY per person, in the case of the Sado mines) and the amount deposited by other Mitsubishi and Mitsui (another large conglomerate) affiliates with the monthly wages they paid around 1945 (an average of over \100 JPY at the Sado mines) shows that the total amount was equivalent to one or two months’ wages-a decidedly small sum. Firstly, for fugitives and those who returned to the peninsula immediately following the end of the war, the reimbursement of such an insignificant amount of money was evidently not worth waiting for. Secondly, compared to the wages they had received up to that point, the money deducted was a relatively small amount for the individuals who decided not to pursue payment. Therefore, this deposited money cannot be used as the basis for forced labor without compensation or for systematic and large-scale exploitation.


  1. The Case of Sado: Daily Life and Treatment

Koreans who came to Japan during the war, including those at the Sado mines, were better off than the peasants who remained in Korea in terms of housing (the rent for both dormitories and housing and use of communal facilities such as bathhouses were either free of charge or far below market price), staple foods (including rice, wheat, and beans), and calorie intake. Just before the end of the war, the menu and amount of food provided were the same for both Korean and Japanese laborers. However, this resulted in a relative shortage of food since Koreans were more voracious eaters than the Japanese. This shortage, in conjunction with the fact that condiments (pepper and garlic) were not provided, caused dissatisfaction among the Koreans. When the distribution system was impacted by a poor harvest and the U.S. bombing campaign in the final days of the war, Koreans faced the same hardships as the Japanese wrought by food shortages. Henceforth, research systematically comparing the living standards of Koreans who came to Japan with those of the farmers who remained in Korea will be required.

More Koreans lived with their families at the Sado mines than in other mines that employed mobilized Koreans. It is speculated that the reason for this was that many Koreans came to Japan as migrant workers and secured employment even before the labor mobilization commenced in 1939.

The higher number of casualties and severe injuries among Koreans compared to Japanese at the Sado mines and other wartime worksites were not due to any particular racial discrimination but merely a result of the coalescence of labor supply and demand at the workplaces. In other words, healthy, young and middle-aged Japanese men were drafted into the army (Japanese troops overseas numbered 950,000 in 1937, 3.58 million in 1943, 5.4 million in 1944, and 7.34 million in 1945. By the end of the war, 60.9% of men aged 20-40 were enlisted in the military, and 2 million had died), the result of which was that young, healthy Koreans worked in the pits in their stead.

In the case of the Sado mines, there were far fewer disputes than at other work sites; since the mobilization began in 1940, there were a total of three cases of group demonstrations by Koreans. These incidents were due to insufficient provisions of food in the dormitories, the rental cost of work equipment, and a “rescue” attempt of colleagues who were reported to the police for gambling.


  1. Runaways are Not Evidence of Forced Labor

The percentage of Korean fugitives at the Sado mines was infinitely lower than at other sites. The desertion of large numbers of workers mobilized during the war was not a phenomenon observed only in Japan but also occurred on the Korean peninsula. Although the number of Japanese workers who fled was far less than that of Koreans, fugitive Japanese workers also abounded.

However, these incidents of desertion cannot be considered cases of “Korean dissent”. Runaways simply sought to avoid working underground in coal and other mines, such as the Sado mines, where approximately 60% of the Koreans were mobilized. Not only those who fled during their time at the mines but all those who used labor mobilization as a safe means of traveling to Japan without incurring travel expenses (fleeing upon arrival in Japan in areas such as Fukuoka or with the help of Korean brokers they had contacted beforehand in major cities such as Osaka, Kyoto, and Tokyo), those who fled after the expiration of their contracts using the money they received from the company for their return ticket, or fled while their family members were repatriated to Korea all remained in Japan to seek employment at companies offering better pay and working conditions.

No special policies or measures were adopted by the Japanese government to find these fugitives, and even if they were caught, they were simply fined the equivalent of 20-40% of their monthly wages, with deportation to Korea reserved as the most severe punishment. Fugitives were also welcomed with high wages at munitions factories and other sites where military installations were being constructed, due in part to the vast capital these establishments possessed but also because labor was in extremely short supply.

Because many of the fugitives who had left the Sado mines and found employment elsewhere actually returned to the mines following the end of the war on August 15, 1945, the Sado mines, like other workplaces, provided them with the funds to return to Korea.


  1. The Need to Bring the Historical Facts to Light

Was the mobilization of Koreans really “forced mobilization”? Although recruitment and official mediation were at times supported on an administrative level by the Government-General or local police, the relationship between Koreans and Japanese companies was fundamentally contractual. Contracts were concluded in Korea or upon arrival at the companies in Japan. The reason for this was that, although in the case of official mediation, there were cases where the Governor-General’s Office employed coercive measures in convincing them to go to Japan, if Koreans point-blank refused to go or fled to another part of Korea, there were no legal means by which Japanese companies or the Government-General could force them to assent. In contrast, conscription involves legal sanctions, and the concept itself is literally that of forced mobilization. In other words, it is clear that “forced mobilization” is a tautology in the case of conscription, but coercion in the case of recruitment and official mediation cannot be defined as “forced mobilization”.

So, can the mobilization of Koreans be considered “forced labor”? Relying on the Forced Labor Convention promulgated by the ILO in 1932 and ratified by Japan in the same year, leftist forces in Korea and Japan argue that Korean wartime mobilization was forced labor and that Japan violated this Convention. However, not only is the interpretation that wartime labor does not correspond to forced mobilization but is a matter of the survival of the community and the nation gaining significant credence, but South Korea ratified the Convention in February 2021, perfectly illustrating the reality that the interpretation and application of the Convention vary according to the circumstances of each country.

The more important issue regarding the “Forced Labor Convention” is the relationship between the concepts stipulated in the laws and the Convention and the historical facts. Whatever these concepts may be, they cannot alter the objective reality of history. Nevertheless, leftist forces are obsessed with the concept of “forced labor” in the above-mentioned Convention and try to bind the Korean and Japanese people to it in order to force upon free citizens a subjective, collective, and ideological “image” of history already formed by the concept of “forced labor” rather than objective historical facts, i.e., a dominating cultivated view of history. Therefore, the most fundamental task is still that of clarifying the historical facts on the issue of whether wartime labor mobilization does or does not constitute “forced labor” and to fight against the existing distorted fictions.

The work Korean wartime laborers engaged in cannot be considered “forced labor”. First, recruitment and official mediation were contractual in nature, and thus the duration of the contract was clearly specified. When the Sado mines recruited Koreans in 1940, the contract period was three years, whereas most other workplaces had two-year contracts.

As a result of labor shortages, Japanese companies offered various incentives to Koreans whose contracts had expired, such as visits home, financial incentives, wage increases, and encouraged them to invite their families so that they might renew and extend their contracts. Although some claim that companies coerced the Koreans into extending their contracts, this was not legally enforceable, and it was, in fact, Korean laborers who frequently reneged on their periods of contract. As many as 40% of workers abandoned their workplaces at their discretion. Companies were, of course, never compensated for this. Koreans had the authority and freedom to decide whether to return to Korea or renew their contracts once the initial contract period concluded, as well as more bargaining power.

The fact that Japanese companies deported Koreans who were negligent of their duties as well as ringleaders in group demonstrations as “delinquents”, and granted workers with personal reasons or extended contracts “temporary leave”-many of whom did not return-also contradicts the claim of “forced labor”. At the time, Koreans (including those at the Sado mines) were paid higher wages than factory hands and clerical workers, were guaranteed the right to be absent from work in the case of illness and other extenuating circumstances, and enjoyed such freedom in their daily lives that alcohol and other sundry activities became an issue. Because the Japanese government and companies gave top priority to the labor productivity of Koreans, there was no mandated or systemic discrimination between Japanese and Koreans in terms of labor, working environment, food, clothing, or housing.

After working hours and on the three to four days off they received each month, they were free to go out. There were no “barbed-wire fences”, “watchtowers”, or “military police with guns” surveilling Koreans as they worked to prevent their escape. Korean “forced labor” is a myth.


  1. Koreans who came to Japan of Their Own Volition

Approximately 2.4 million Koreans traveled to Japan during the period of wartime labor mobilization (1939-45). However, only about 720,000 came to Japan under the wartime mobilization of Japanese companies and the Tokyo government. As the gates to Japan were thrown wide open with the commencement of wartime mobilization, about 1.68 million people emigrated to the home islands, the majority of whom were itinerant workers who had come to stay for several years and earn money. Due to the marked weakening of restrictions on travel to Japan and the extreme shortage of labor, there were also many stowaways that were not reflected in the statistics, and their number is consequently unknown. At the time, these migrant workers who came to Japan to earn money irrespective of the wartime mobilization were known in Japan as “free laborers”.

During the same period, about 25% of the 720,000 people who came to Japan under wartime mobilization were recruited, 40% were hired through official mediation, and 35% were conscripted. Since recruitment was fundamentally voluntary, and about 40% of those recruited through official mediation and conscription deserted and became free laborers, 55% (25%+75%*0.6) of the wartime laborers were free. There were undoubtedly many workers among those who came to Japan through official mediation or conscription who willingly accepted their placement at sites offering high incomes (for example, those who extended their contracts or found employment at other workplaces after the expiration of their contracts), but precisely how many is still unknown. Ultimately, even by conservative estimates, 45% of the wartime workforce, or about 320,000 people, moved to Japan regardless of whether they wanted to or not.

Because 320,000 out of 2.4 million cannot be used to define the nature of Korean emigration to Japan between 1939 and 1945, precedence must be given to the 2.08 million. Moreover, as seen in the case of the Sado mines, there were already Korean workers who had emigrated to Japan before September 1939. As the example of the Sumitomo Konomai Gold Mine shows, they played an essential role in directing and managing the wartime laborers, and this would have been the case at other sites, including the Sado mines. These more than 2.08 million free laborers and 320,000 wartime workers were not mutually exclusive; they coexisted in the Japanese labor market, sometimes working in the same factories or mines. Escape was a route for wartime workers to become free laborers, and sites that employed wartime workers had to be aware of the existence of free laborers in more favorable conditions, such as surface workers and relatively high wages.

Overall, this period was the first time in its history that Korea saw a veritable explosion in free migrant work in such a short period of time, which can be largely attributed to the free expatriates who pioneered an expanded sphere of economic activity. It was during this period that the international migration that unfolded during the so-called “first wave of globalization” from the 1870s to World War I and the Korean international migration that developed in the wake of liberation began. Even though this migration was colonial in form and took place during the war, the fundamental nature of it was that of overseas migration. The term “colonial” refers to the fact that this migration took place under the rule of the Japanese colonizers and that migrants were treated as “second-class citizens” in accordance with the rapidly changing policies on Koreans traveling to Japan from 1937 onward. While “second-class citizen” may allude to the possibility of racial discrimination against Koreans due to their “second-class” status, it also implies that Koreans were foreigners and prisoners of war who had rights and obligations as Japanese “nationals”. This is suitably expressed in the fact that Koreans were subject to “conscription” and could choose to “run away”, if they so wished.

The “wartime” nature of Korean wartime immigration refers to the fact that labor immigration took place under the exceptional circumstances of war when freedom of employment was restricted; that is, Koreans were obliged to work in occupations they shunned in coal mines and other mines, where they received preferential treatment. At the same time, the war resulted in the rapid and large-scale expansion of possibilities for immigrants in a very short period of time. The labor shortage brought about by the massive conscription of Japanese men dictated that the treatment of Koreans be determined not by market equilibrium but by the extra-economic policies of the Japanese government and corporations, paradoxically resulting in a situation in which the wages and benefits the colonized people were afforded exceeded their human capital. Wartime migration thus developed in seemingly contradictory and complex ways.

I propose that the movement of Koreans to Japan during 1939-45 be understood as a form of “colonial and wartime overseas migration”, and that the wartime labor mobilization be seen as a facet of it. Koreans and Japanese alike must identify with this perspective in accepting the registration of the Sado mines as a World Heritage site.


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