Three sailors at Tanegashima ignite Japanese unification — and a century of religious massacre

Sengoku Japan before the matchlocks

In September 1543, the Japanese archipelago was in the middle of the Sengoku Jidai — the Warring States period — that had begun with the Onin War of 1467 and would end, after a fashion, with Toyotomi Hideyoshi's pacification of the country in the 1590s. The Ashikaga shogunate that had nominally governed Japan since 1336 was, by 1543, a powerless court establishment surrounded by warlords (sengoku daimyō) who had carved up the country into perhaps two hundred competing domains. Each domain was militarized; each was actively contesting borders with its neighbors; each was investing in defensive castle architecture, in the recruitment and training of samurai retainers, and in the production of weapons.

The weapons were good. Japanese sword-craft of the late Muromachi period (the years immediately preceding 1543) is, by the standards of any pre-industrial sword-making tradition, exceptional. The folded steel construction, the differential hardening that produced the curved cutting edge, the polished surface that made the hamon (the temper line) visible — all of this was the product of centuries of refinement by hereditary swordsmith families. The Bizen tradition in central Honshū, the Sōshū tradition around Kamakura, the Yamato tradition near Nara, and the Yamashiro tradition around Kyoto each had distinctive styles. The swordsmiths were among the most prestigious craftsmen of Japanese society and the swords they made were, in many cases, individually named and treasured weapons that descended through samurai families across generations.¹

For missile weapons, Japanese armies relied on the bow. Japanese archery in 1543 was at a high level: the yumi, the long asymmetrical Japanese bow, drew at substantial weights and could be shot accurately to several hundred meters. Mounted archery (yabusame) was an aristocratic skill cultivated by samurai. Foot archery using composite-bow infantry was the principal form of mass missile fire on Japanese battlefields.

What Japanese armies did not have was firearms. Some isolated examples of early Chinese gunpowder weapons had reached Japan via the Korean peninsula in the fourteenth century, but they had not been adopted; they were too crude, too unreliable, and too unfamiliar to displace the bow. The Portuguese matchlock that landed in 1543 was something else.

The political situation in 1543 was that no daimyō controlled more than a fraction of the country. Three rival families dominated central Japan: the Imagawa, the Hōjō, and the Takeda. The Mōri were rising in the west; the Date were the strongest force in the northeast. Oda Nobunaga, the warlord who would eventually take the matchlock and use it to break the older order, was nine years old in 1543 — the heir to a small and not particularly important domain in central Owari province. The country had been at intermittent war for seventy-five years and was no closer to unification than it had been at the start.

The transmission

The Chinese junk that grounded on the southern tip of Tanegashima in September 1543 was not an isolated incident. Portuguese traders had been operating in East Asian waters for several decades, working out from their bases at Goa (taken from the Bijapur Sultanate in 1510) and Malacca (taken from the Malay sultanate in 1511). By the 1540s, Portuguese ships were regular visitors to Chinese coastal ports — though they were not yet welcome there — and were beginning to make contact with Japanese ports through Chinese junks operating outside the official Ming tribute trade. The three Portuguese who landed at Tanegashima — named in Portuguese sources as Antonio da Mota, Francisco Zeimoto, and Antonio Peixoto — were merchants traveling on a Chinese ship that had been blown off course. Their landing was accidental. Their cargo, however, included matchlock arquebuses they had been carrying as part of their personal equipment.

Tanegashima Tokitaka, the fifteen-year-old lord of the small island, watched a demonstration on the beach. The arquebus could fire a lead ball with sufficient force to penetrate plate armor and at sufficient range to be deployed effectively against a charge. Tokitaka understood immediately what he was seeing. He paid the Portuguese the substantial sum of one thousand ryō of gold for two of the weapons, and he handed them to his chief swordsmith, Yaita Kinbei, with orders to reproduce them.²

The technical challenge was not trivial. The arquebus was a complex assembly: a smoothbore barrel, a stock, a serpentine matchlock mechanism that lowered a smouldering match into a flash-pan, a touchhole connecting flash-pan to barrel chamber. The barrel had to be straight, of consistent bore, capable of withstanding the explosive pressure of black powder. The matchlock mechanism required precision metalwork. Yaita Kinbei spent months on the problem; one tradition has it that he was unable to seal the breech of the barrel until a Portuguese sailor visiting Tanegashima the following year showed him the technique, and that Yaita gave his daughter to the Portuguese in exchange for the instruction. The detail is doubtful but the outcome is not: by 1545, Tanegashima-style arquebuses (called teppō in Japanese, after the Portuguese name) were being produced on Tanegashima.

Photograph by PHGCOM. Akō Temple Museum, Japan. CC BY-SA 3.0 via Wikimedia Commons. · CC BY-SA 3.0

The technology then propagated rapidly. Tokitaka allowed the design to be replicated by other domains. Sakai, the major commercial port on Osaka Bay, became the largest Japanese center of arquebus production by the 1550s; Ōmi province in central Honshū and Kunitomo in northern Ōmi became the next major centers. Within thirty years of the 1543 landing, Japan was producing more firearms than all of Europe combined. By the 1570s, every major daimyō had access to substantial numbers of arquebusiers, and the tactical question on Japanese battlefields had shifted from how to deploy bowmen to how to deploy gunners.³

What changed in Japanese warfare and politics

The military consequences arrived faster than any non-Japanese contemporary observer believed possible. The decisive demonstration was the battle of Nagashino in 1575.

Nagashino is a fortress in modern Aichi prefecture. In 1575, the Takeda army under Takeda Katsuyori was besieging it; an Oda-Tokugawa relief force under Nobunaga and Tokugawa Ieyasu arrived to break the siege. Nobunaga, by 1575 the most ambitious of the major daimyō and the warlord with the largest investment in firearms, deployed three thousand arquebusiers in rotating volleys behind a wooden palisade. The Takeda cavalry — once considered the most fearsome force in Japan, the heirs of Takeda Shingen's celebrated mounted samurai tradition — charged the palisade in successive waves. Each wave broke against the volley fire. Modern military historians debate whether Nobunaga actually used a true rolling-volley system or whether the firing was less coordinated, but the outcome is not in question: the Takeda cavalry was destroyed as a fighting force, the Takeda clan as a major power was finished, and the battle is conventionally treated as the moment medieval Japanese warfare ended.⁴

Nagashino was the proof of concept. Within a generation it became the model. By the 1580s, every major Japanese daimyō was deploying massed arquebusier formations behind palisades; by Hideyoshi's Korean invasion of 1592–1598, the Japanese expeditionary force was substantially better armed with firearms than the Korean and Ming Chinese armies it fought. The unification of Japan under Nobunaga (assassinated 1582), then Hideyoshi (died 1598), then Tokugawa Ieyasu (Tokugawa shogunate established 1603) — the political transformation that ended the Sengoku period and produced the centralized state that would govern Japan for 268 years — runs directly through the matchlocks that washed up on Tanegashima.

The Tokugawa state that resulted was, in important respects, distinctively Japanese in its eventual settlement. The shogunate moved by the early seventeenth century to substantially restrict the manufacture and possession of firearms — partly through the famous katanagari (sword hunt) edicts initiated by Hideyoshi in 1588, which disarmed the peasantry, partly through Tokugawa controls on gunpowder production and arquebus manufacture, partly through cultural policies that re-elevated the sword as the prestige weapon of the samurai class. By the late seventeenth century, Japanese firearm production had been largely capped at the volume Tokugawa governance considered safe. The country that had pioneered mass firearm warfare in the late sixteenth century would, by the time Commodore Perry's American steamships arrived in 1853, have stagnated technologically for two centuries and would be operating with arquebuses essentially unchanged from the Tanegashima design.⁵ This is the famous "giving up the gun" pattern — partly real, partly mythologized in twentieth-century histories — that has been the subject of substantial scholarly debate.

The Jesuits arrive

The Portuguese trade routes that brought matchlocks to Tanegashima also brought, six years later, the Jesuit mission. Francis Xavier — Spanish by birth, Portuguese by patronage, founding member of the Jesuit order with Ignatius of Loyola — landed at Kagoshima in southern Kyūshū on August 15, 1549. Xavier had spent the previous nine years missionizing in Goa and the Malabar coast; Japan was the eastern frontier of the global mission program of the Society of Jesus.⁶

Xavier and his small party of Jesuits found Japanese society more receptive than they had expected. The lord of Kagoshima, Shimazu Takahisa, allowed Xavier to preach in his domain in exchange for the prospect of Portuguese trade. The Japanese were curious about the foreign teaching; the early Jesuits were intelligent men who learned Japanese and adapted their preaching to local categories; the cultural distance was bridgeable. By the time Xavier left Japan in 1551 (he died in China the following year), the mission had baptized perhaps a thousand converts.

The mission then accelerated. Xavier's successors — Cosme de Torres, Luis de Almeida, the great mission-organizer Alessandro Valignano (active in Japan 1579–1582 and later) — built the Japanese mission into the most successful Jesuit enterprise outside Europe. By 1580, perhaps 130,000 Japanese had been baptized. By 1600, the figure may have reached 300,000 — a number that is debated but whose order of magnitude is supported by independent Japanese sources.⁷ The Christianized regions were concentrated in Kyūshū and the western parts of Honshū where Portuguese trade was concentrated; the daimyō of these regions converted partly out of religious conviction and partly because Christian status was understood as part of the Portuguese commercial relationship.

The relationship between conversion and trade was the structural feature that would, eventually, make the religion impossible. The Portuguese ships were Catholic; the trade contracts depended on Catholic intermediaries; some daimyō who wanted access to Portuguese guns and silk converted in part to secure that access. When the political logic shifted — when the Tokugawa state decided that Catholicism was a threat to its consolidation — the religious community had no protection. The structural vulnerability of having been a foreign-trade religion was inseparable from the religion's initial spread.

What was replaced — and what came instead

The arrival of Catholicism and the firearms together produced the most concentrated foreign cultural influence on Japan since the Buddhist transmission of the sixth century. The hundred-year period from 1543 to the sakoku edict of 1639 — sometimes called the namban-jin jidai ("Period of the Southern Barbarians" in Japanese, the namban-jin being the Portuguese and Spanish) — saw substantial introductions across multiple cultural domains.

Firearms restructured Japanese warfare and political consolidation, as discussed.

Catholic missionary infrastructure introduced new architectural forms (the Jesuit churches at Nagasaki, Funai, and elsewhere were built in mixed Iberian-Japanese style and represented the first non-Buddhist non-Shintō major religious architecture in the country), new musical traditions (Western polyphonic music was performed in Japanese churches by the late sixteenth century), new visual conventions (Western perspective, oil painting, and Christian iconography), and new educational structures (the Jesuit seminario at Arima trained Japanese converts in Latin, theology, and Western sciences from 1580).

The Portuguese trade introduced new foods. Tempura is from the Portuguese tempora (the Lenten fast vegetable preparations). Kasutera (sponge cake) is from Castile. Pan (bread) is the Portuguese word, surviving in modern Japanese where it competed with no equivalent native term because Japanese bakery culture did not exist before the contact. Japanese cuisine acquired a permanent set of Portuguese-derived elements that survived the eventual political severance.

Western medicine made its first Japanese converts during this period. The Jesuit-run hospital at Funai (modern Ōita) was the first major non-Chinese medical establishment in Japan; Japanese doctors trained in the European medical practice survived in some lineages even after the religious suppression and contributed to the rangaku (Dutch learning) tradition that would re-emerge in the eighteenth century.

What the new influences replaced was a partly closed cultural ecology. Pre-1543 Japan had been substantially sealed against direct European contact; the only foreign cultural influence had been Chinese and Korean, and that influence had been mediated through the Buddhist clergy and the gozan monastery network. The Portuguese trade ended this isolation for nearly a century. Japanese knowledge of European geography, of European astronomy (the Jesuits taught Ptolemaic and later early Copernican astronomy), of European medicine, of European visual art, was, by 1600, more extensive than at any point before the Meiji opening of the 1860s. The namban-jin jidai was a brief but real engagement with the European intellectual world.

The bill

The cost came within a generation of the Jesuits' arrival. Toyotomi Hideyoshi, the second of the great unifiers, became increasingly suspicious of the Christian enterprise as he consolidated his power. In 1587, after his successful campaign against Shimazu in Kyūshū, Hideyoshi issued the first edict expelling the missionaries. He did not enforce it; the trade and the missionaries continued. But the policy had been declared.

In 1597, Hideyoshi's patience ran out. The San Felipe incident — a Spanish Manila galleon driven onto the Japanese coast in 1596, whose pilot was reported (probably falsely) to have boasted that Spanish missions were the advance guard of Spanish military conquest — gave Hideyoshi the political cover to act. Twenty-six Christians were arrested at Kyoto and Osaka and condemned to death by crucifixion. The group included six Franciscan missionaries (mostly Spanish), three Japanese Jesuit brothers, and seventeen Japanese laymen — including three children: Luís Ibaraki (12), Tomás Kosaki (15), and Antonio (13). The twenty-six were marched 800 kilometers from Kyoto to Nagasaki, with their left ears cut off at Kyoto as ritual mutilation along the way. They were crucified on a hill overlooking Nagasaki harbor on February 5, 1597. The execution was conducted publicly. Eyewitness Jesuit accounts describe the prisoners singing hymns from their crosses until they were killed by spear thrusts up under the ribs, the standard Japanese execution method on the cross.⁸

Hideyoshi died the next year. The Tokugawa shogunate that consolidated under Ieyasu after 1603 maintained, then intensified, the persecution. The 1614 expulsion edict banned Christianity outright across Japan. From 1614 onward, Japanese Christians who refused to apostatize were systematically tortured and killed. The methods were specific and well documented: the fumi-e, a bronze plaque depicting Christ or the Virgin that suspected Christians were forced to step on (refusal was death); suspendio (the pit), in which the victim was suspended head-down in a pit of excrement and slowly bled out from incised wounds — the technique that famously broke the apostate Jesuit Cristóvão Ferreira in 1633 and forms the basis of Endō Shūsaku's novel Silence; ana-tsurushi (hanging in the pit, a variant); burning at the stake; crucifixion; live burial; and standardly drowning at sea.⁹

The death toll across the systematic persecution from 1614 through the 1640s is uncertain. Jesuit records — partial because the persecution destroyed many — list approximately 3,000 named martyrs through this period; modern Japanese Catholic scholarship estimates the total at perhaps 5,000 to 8,000 named Christians killed across roughly thirty years.¹⁰ The number is small relative to other persecutions in this atlas (the Antonine Plague's 5–10 million; the Atlantic slave trade's millions; the Columbian exchange's 50+ million indigenous American deaths), but it represents the systematic state-organized eradication of an entire religious community across a single generation.

Shimabara

The culmination of the persecution was the Shimabara Rebellion of 1637–1638. The Shimabara peninsula in southern Kyūshū had been one of the most heavily Christianized regions of Japan; many of its peasants had been baptized in the late sixteenth century, and although the formal religion had been suppressed for two decades by the 1630s, residual Christian practice and identity persisted in covert form (the kakure kirishitan, or "hidden Christians" tradition).

The immediate cause of the rebellion was tax oppression. The local daimyō Matsukura Shigeharu — granted the Shimabara domain in 1614 — had imposed catastrophic taxation on his peasants in order to fund his ambitions of conquering Manila. (The Tokugawa shogunate eventually punished him for these taxes, though only after Shimabara had broken into open rebellion.) When peasants could not pay, Matsukura's officials punished them brutally — the Mino dance, a torture in which a peasant in a straw raincoat was set on fire, was a recurring practice. By 1637, accumulated grievance over taxation had combined with residual Christian identity to produce a coordinated rebellion.

The rebels — perhaps 37,000 strong, mostly Christian peasants and a smaller number of rōnin (masterless samurai) including fugitives from the suppressed Christian samurai households of Kyūshū — gathered at Hara Castle, an abandoned fortress on the Shimabara peninsula. Their nominal leader was Amakusa Shirō, a sixteen-year-old Christian charismatic figure whose name and image were attached to the rebellion. The shogunate responded with overwhelming force. An army of 125,000 was assembled — the largest single Japanese military operation since Hideyoshi's invasion of Korea — and besieged Hara Castle from December 1637 through February 1638.

The siege ended on April 12, 1638. The shogunate's forces broke the castle's defenses; nearly every defender was killed in the assault and the subsequent slaughter. Modern estimates of the death toll vary from 30,000 to 40,000 rebels killed; the standard figure is approximately 37,000. Women, children, the wounded — all were killed. Amakusa Shirō's head was displayed in Nagasaki. The shogunate's forces lost approximately 10,000–13,000 troops killed in the siege.¹¹

The Shimabara Rebellion was the largest single act of religious-political violence in Japanese history. It exceeded in scale every earlier Buddhist persecution, every earlier samurai factional conflict. Within two years of Shimabara, Japan was sealed: the 1639 sakoku edict expelled the Portuguese and forbade Japanese subjects from leaving the country; only a tightly controlled Dutch trading post on the artificial island of Dejima remained as a foreign presence. The country closed itself for the next two hundred and fifteen years, until Commodore Perry's American steamships forced re-opening in 1853–1854.

What the cost was

The matchlocks that arrived in 1543 produced two consequences inseparable from each other in their actual historical entanglement.

The first consequence was the political consolidation of Japan. The Tokugawa state that emerged from the warring states period was a centralized polity with a coherent administrative apparatus, a working tax system, urban markets at unprecedented scale, a common literary culture, and 250 years of internal peace after the late sixteenth century's wars of unification. The matchlock was the technological precondition for the unification; the unification produced one of the more remarkable peaceful periods in early modern world history.

The second consequence was the most violent religious suppression in Japanese history. Several thousand named Christians killed across thirty years of systematic torture and execution. Approximately 37,000 Christian peasants and rōnin slaughtered at Shimabara in 1638. Two centuries of national isolation under sakoku, during which the kakure kirishitan communities maintained a covert Christianity through generations and during which the broader Japanese society was sealed from European contact in ways that produced both internal cultural cohesion and growing technological lag.

These consequences are not separable. Tokugawa Ieyasu's consolidation depended on the firearms that the same trade brought; the firearms came on the same ships that brought the missionaries; the missionaries created the Christian community that the consolidating state then suppressed. To tell either story without the other is to mis-tell both.

A particular feature of the Tanegashima arc deserves explicit notice in the Hidden Threads framework. This is one of the few cases in the atlas of a transmission that produced both a major gift to the receiving culture and a major cost paid by the receiving culture itself. Most cost-bearing transmissions in this atlas displace the cost onto a third party (the indigenous American populations who paid the cost of the Columbian exchange while Europe got the tomatoes and the silver; the African populations forcibly transported to the Americas while the resulting agricultural systems enriched the European economy). The Tanegashima arc is unusual in that the gift (firearms enabling unification) and the cost (the Christian persecution and Shimabara) were both internal to Japan. The Japanese state of the early seventeenth century received a transformative technology and paid for it by killing tens of thousands of its own citizens who had embraced an associated religion.

The surviving traces are visible in modern Japan. The 26 Martyrs Monument on Nishizaka Hill in Nagasaki marks the 1597 execution site. The remains of Hara Castle on the Shimabara peninsula, burned and razed after 1638, stand as a designated historical site. The kakure kirishitan sites in the Goto Islands and the rural Nagasaki region — added to the UNESCO World Heritage list in 2018 — preserve the memory of the underground Christian generations who maintained their faith in secret through the sakoku centuries. The 16th-century Nanban screens in museums in Lisbon, Kobe, and Osaka show the moment of contact from the Japanese view: Portuguese ships at harbor, Portuguese sailors disembarking in their elaborate dress, Japanese onlookers regarding them with curiosity that contemporary viewers cannot read without knowing what came next.