Slavery in Japan
Slavery in Japan existed in several forms from antiquity through the early modern period, alongside other systems of unfree and coerced labor. In early Japanese sources, enslaved people included groups referred to as seikō and later nuhi under the ritsuryō legal codes, and historians debate how these institutions compare with slavery and serfdom in other societies.
By the late medieval and Sengoku periods, the buying and selling of captives and other dependent people remained widespread, including the export of Japanese people through the Portuguese slave trade in the 16th century. Under Toyotomi Hideyoshi, slavery was officially banned in the late 16th century, but other forms of legally sanctioned coercion and dependency continued, including penal “non-free labor” under early Edo-period law.
In the 20th century, Japan’s wartime empire used large-scale forced labor and prisoner-of-war labor during the Second Sino-Japanese War and the Pacific War, including on projects such as the Burma Railway. The Imperial Japanese military also operated the system of military brothels commonly referred to as “comfort women”, which has been widely described as involving sexual slavery.
Early slavery in Japan
The export of a slave from Japan is recorded in the 3rd century Chinese historical record Wajinden, but it is unclear what system was involved, and whether this was a common practice at that time. These slaves were called seikō.In the 8th century, slaves were called Nuhi and laws were issued under the legal codes of the Nara and Heian periods, called Ritsuryōsei. These slaves tended farms and worked around houses. Information on the slave population is questionable, but the proportion of slaves is estimated to have been around 5% of the population.
Slavery persisted into the Sengoku period even though the attitude that slavery was anachronistic seems to have become widespread among elites. Somewhat later, the Edo period penal laws prescribed "non-free labor" for the immediate family of executed criminals in Article 17 of the Gotōke reijō, but the practice never became common. The 1711 Gotōke reijō was compiled from over 600 statutes promulgated between 1597 and 1696.
War prisoners and Genin
During the Sengoku period, Japanese Daimyos and merchants often sold off prisoners of battle into slavery. Portuguese sources, corroborated by Japanese texts like Koyo Gunkan and Hojo Godaiki, describe “the greatest cruelties” inflicted during conflicts such as the 1553 Battle of Kawanakajima and the 1578 Shimazu campaigns. Captives, particularly women, boys, and girls, faced violence, with communities in regions devastated. The inter-Asian slave trade, including Wokou piracy, further intensified suffering, with Zheng Shungong’s 1556 report noting 200–300 Chinese slaves in Satsuma treated “like cattle” for labor, a fate shared by many Japanese.When the Imjin War broke out between Japan with Korean Joseon kingdom between 1592-1598, slavery of Korean captives by three Japanese invaders also occurred. Francesco Carletti, an Italian merchant who visit Japan during that time, was recorded to bought five Korean slaves for price of about 12 scudi. After baptizing them, he took them to Goa, India, where he set four of them free. It has been suggested that Korean slaves were not traded at high prices, and therefore were cheap. Even if they were bought at low prices, they still needed to be fed on the way, which was an additional expense. Thus, Japanese researcher Watanabe Daimon suspected the reason Carletti freed four of his slaves was possibly because he thought there was no hope of reselling them in the slave market.
The custom of geninka encompassed practices resembling slavery. Individuals were exchanged for money, including children sold by parents, self-sold persons, those rescued from unjust execution, and debt-bound workers. Japanese rulers imposed geninka as punishment for serious crimes or rebellion, often extending it to the perpetrator’s wife and children. Women who fled their fathers or husbands to seek shelter in a lord’s house were sometimes transformed into genin by the lord. During famines or natural disasters, individuals offered themselves as genin in exchange for food, clothing, and shelter. Japanese lords also demanded that retainers relinquish their daughters to serve in their manors, treating them as genin. Additionally, the genin status could be hereditary, perpetuating bondage across generations.
Portuguese Slave Trade in Japan
Background
Portuguese merchants in Sengoku-era Japan viewed unfree labor forms, like master-servant relationships, as slavery, applying terms like criado, servo, and captivo to Japanese classes such as fudai no genin, genin, shojū, and yatsuko. These groups, often engaged in agricultural or domestic work, were sometimes sold under customary law. The term escravo included nenki hōkō which was not common until Edo Period, despite their distinct status, causing misunderstandings. Gaspar Vilela described peasants as slaves due to economic dependence, while Cosme de Torres likened servants’ subservience to Roman vitae necisque potestas. Peasants could be sold as tax collateral, blurring free-unfree distinctions. Human trafficking was common. Some Japanese entered servitude voluntarily for travel to Macau, often breaking contracts upon arrival, driven by civil war taxes.By the early 16th century, African slave trade networks supplied Portugal’s Atlantic islands and southern regions, enabled by low costs and accessible sources. Asian Portuguese territories lacked large-scale plantations, limiting slave demand to domestic labor. Asian slaves, including Japanese and Chinese, were valued as household servants, artisans, or status symbols, with high transport costs deterring large-scale trade to South America or Portugal. Merchants prioritized spices over slavery. In 16th-century Portugal, Chinese and Japanese slaves were far fewer than East Indian, Muslim convert, or African slaves. In Mexico City, Asian slaves, mostly from the Philippines and India, numbered 88 in a 1595 inquisition survey, compared to 10,000 African slaves. An average of 30 slaves were on each galleon, with an estimated 3,630 "Indios Chinos" slaves entering Nueva España between 1565 and 1673. In Mexico City, 22% of the Asian population were women. One-third of these "indios chinos" were slaves, mostly from the Philippines or India, with very few from Japan, Brunei, or Java. Asian slavery was significantly less prevalent than the Atlantic slave trade.
In 1570, King Sebastian I banned ships under 300 or over 450 tons. Portugal’s fleet never exceeded 300 ships, with only 34 of 66 returning from India. Nau ships, used for Portugal-India and Macau-Japan trade, reached 600 tons, carrying 400–450 people, including crew, passengers, soldiers, and limited slaves. A nau or galleon with a cargo capacity of 900 tons or more, could carry 77 crew, 18 gunners, 317 soldiers, and 26 families. The Macau-Japan route, limited to a yearly cycle due to trade winds, prioritized silk, with cargo holds of 250–400 cubic meters, supplemented by Japanese goods like sulfur, silver, and lacquerware, affecting passenger capacity. However, between 1594 and 1614, the annual ship from Macao failed to arrive on eight occasions, indicating the instability of navigational success. Lucio de Souza assessed Portuguese ships’ slave-carrying capacity, but Guillaume Carré criticized the lack of precise data.
Papal decrees and the 1542 New Laws of the Indies banned enslaving East Asians, legally indios. In 1571, King Sebastian I of Portugal banned Japanese human trafficking, following a 1567 law prohibiting the slave trade from Ethiopia, Japan, and China, with further bans issued later. In 1591, Pope Gregory XIV’s bull Cum Sicuti ordered reparations for enslaved indios in Philippines, threatened slave owners with excommunication, and mandated their liberation. King Philip III also prohibited the transfer of female slaves to Mexico, reflecting growing efforts to restrict slavery despite uneven enforcement. Portugal prohibited Japanese and Chinese slave trading in 1595, with 1605 decrees allowing enslaved Japanese in Goa and Cochin to seek freedom.
The Spanish 1542 New Laws offered some recourse, as seen in Gaspar Fernández’s 1599 liberation in New Spain, where he argued his enslavement lacked just war justification, and Japanese were equivalent to free indigenous people, citing that Spanish laws banning the enslavement of Japanese. Only 4 of 225 identified chino slave sent from Philippines to Acapulco were Japanese.
Filippo Sassetti saw some Chinese and Japanese slaves in Lisbon among the large slave community in 1578, although most of the slaves were black.
The Portuguese "highly regarded" Asian slaves like Chinese and Japanese. The Portuguese attributed qualities like intelligence and industriousness to Chinese and Japanese slaves which is why they favoured them.
Arrival of Portuguese
After the Portuguese first made contact with Japan in 1543, a large-scale slave trade developed in which Portuguese purchased Japanese as slaves in Japan and sold them to various locations overseas, mostly in Portuguese-colonized regions of Asia such as Goa but including Brazil and Portugal itself, until it was formally outlawed in 1595. Many documents mention the large slave trade along with protests against the enslavement of Japanese. Although the actual number of slaves is debated, the proportions on the number of slaves tends to be exaggerated by some Japanese historians. At least several hundred Japanese people were sold; some of them were prisoners of war sold by rival clans, others were sold by their feudal lords, and others were sold by their families to escape poverty. The Japanese slaves are believed to be the first of their nation to end up in Europe, and the Portuguese purchased a number of Japanese slave women to bring to Portugal for sexual purposes, as noted by the Church in 1555. Sebastian of Portugal feared that this was having a negative effect on Catholic proselytization since the slave trade in Japanese was growing to larger proportions, so he commanded that it be banned in 1571. However, the ban failed to prevent Portuguese merchants from buying Japanese slaves and the trade continued into the late 16th century.The Jesuit Luis de Almeida, in 1562, documented a group of Chinese female slaves at Tomari Port in Kawanabe District, Satsuma Province. According to his account, these women were captured by the Japanese during wars in China and sold, subsequently purchased by the Portuguese. Lacking the authority to regulate the commercial activities of merchants, Almeida could only request that the honor and safety of these women be safeguarded during their voyage.
Japanese slave women were also sold as concubines to Asian lascars, along with their European counterparts serving on Portuguese ships trading in Japan, mentioned by Luis de Cerqueira, a Portuguese Jesuit, in a 1598 document. Japanese slaves were brought by the Portuguese to Macau, where some of them not only ended up being bought by the Portuguese, but as slaves to other slaves, with the Portuguese owning Malay and African slaves, who in turn owned Japanese slaves of their own.
Jesuit-established organizations, such as confraternities and the Nagasaki Misericórdia, undertook efforts to rescue Japanese slaves, particularly women, from ships and brothels. The memoirs of Afonso de Lucena and letters of Luis Fróis concur regarding the treatment of captives during the Battle of Nagayo Castle in March 1587, reflecting Lucena’s concerns about their legitimacy. After Christmas 1586, Lucena urged Ōmura Sumitada, whose health was failing, to free unjustly held captives, leveraging the threat of withholding confession. The Jesuits strategically withheld confession or sacraments to compel moral conduct, especially among influential converts.
Moreover, bishops and their representatives condemned brothels and private prostitution as “workshops of the devil.” The fourth article of the Constitutions of Goa prohibited brothel ownership and operation, imposing fines and public shaming on violators, while mandating the liberation of slaves coerced into prostitution. Thus, the Jesuits endeavored to eradicate immoral practices like prostitution while advancing slave rescue and evangelization through conversion.
Japanese socio-economic practices, such as nenkihōkō, were often conflated with slavery by Europeans but involved distinct treatment. Bishop Cerqueira noted that nenkihōkō met European moral theology standards, such as Silvestre Mazzolini’s criteria, requiring voluntary agreement and awareness of freedom. However, economic pressures, like taxes imposed by non-Christian lords, led parents to sell children into servitude, often under “great” rather than “extreme” necessity, reflecting cultural relativism in assessing hardship. Cosme de Torres likened the power of Japanese lords over servants to Roman vitae necisque potestas, suggesting that peasants, used as tax guarantors, faced conditions akin to slavery, with little distinction between servitude and enslavement. Women seeking refuge from abusive situations could be transformed into genin by lords, a practice Jesuits deemed tolerable only if the individual was justly condemned for a crime; otherwise, missionaries advocated for their liberation through confession.
In Portuguese India, Valignano and fellow Jesuits lacked jurisdiction to intervene in slave transactions, which were subject to secular courts. Priests were limited to providing ethical guidance, rendering the cessation of the practice unfeasible, and it persisted into the seventeenth century. In Japan, the Macao Diocese, established in 1568, oversaw Japan from 1576, but the absence of a resident bishop impeded the resolution of local issues. The Jesuits’ attempt to establish an independent diocese required explicit approval from Rome. Given the limited impact of admonitions and recommendations, missionaries sought to navigate local social dynamics within the constraints of ecclesiastical law. They categorized labor into three forms: servitude equivalent to slavery, a tolerable non-slavery condition, and an unacceptable state. This distinction is believed to have led missionaries to reluctantly acquiesce to local customs. Furthermore, missionaries critical of the Portuguese slave trade in Japan, unable to directly prevent Portuguese merchants’ slave purchases due to insufficient authority, advocated for reframing Japan’s prevalent perpetual human trafficking as a form of indentured servitude to align with local practices while mitigating the harshest aspects of exploitation.
Alessandro Valignano’s strategy of “tolerance” and “dissimulation” allowed Jesuits to navigate local customs while condemning egregious abuses. The 1592 Dochirina Kirishitan emphasized redeeming captives as a Christian duty, rooted in Christ’s atonement, yet Jesuits lacked the authority to enforce the prohibition of slavery, as Valignano repeatedly argued.
The Jesuit response to slave treatment was shaped by theological distinctions between perpetual slavery and temporary servitude, with the latter deemed acceptable for Japanese and Chinese slaves, as they were not war captives or "common slaves." Recognizing their limited power, the Jesuits sought to reform Japan's system of perpetual slavery into indentured servitude. Some missionaries, driven by humanitarian concerns, signed short-term ownership certificates to prevent the greater harm of lifelong enslavement. The practice of issuing permits for temporary servitude in Japan, recognized as early as 1568 with Melchior Carneiro's arrival in Macao, gained official or local acknowledgment. The intervention of missionaries in Japan, particularly in issuing short-term permits, likely peaked between 1568 and the period following the 1587 Bateren Edict, when permit issuance requirements became stricter or were increasingly restrained. Their bitter interventions, such as signing short-term servitude certificates to prevent perpetual slavery, were banned by 1598 after criticism from figures like Mateus de Couros, who viewed such involvement as misguided.
The Jesuits, previously constrained by limited authority in Japan, experienced a pivotal shift with Pedro Martins’ consecration as bishop in 1592 and his arrival in Nagasaki in 1596. As the first high-ranking cleric in Japan since Francisco Xavier, Martins acquired the authority to excommunicate Portuguese merchants engaged in the trade of Japanese and Korean slaves. However, the Jesuits’ dependence on financial support from the Captain-major and the bishop’s limited secular authority posed challenges. The Captain-major, as the supreme representative of Portuguese royal authority in Japan, held significant power; opposing him without royal endorsement made excommunication theoretically feasible but practically uncertain.
Ultimately, Martins, alarmed by the social disruption caused by the trade in Japanese and Korean slaves, resolved to pronounce excommunication against human trafficking. After his death, Bishop Cerqueira reinforced this anti-slavery policy, referring the issue, which required secular authority, to the Portuguese crown. After 1598, Bishop Luís de Cerqueira intensified pressure on Spanish and Portuguese authorities to abolish temporary servitude of Japanese and Korean individuals, but the Portuguese slave trade reportedly grew. Despite efforts like Bishop Cerqueira’s lobbying for secular laws and King Philip III’s 1605 decree allowing Japanese slaves in Goa and Cochin to seek justice for illegal enslavement, the trade persisted due to profitability and weak enforcement.