The Imjin War: Japan's Sixteenth-Century Invasion of Korea and Attempt to Conquer China

by Samuel Hawley

  Oribe then wrote that the island’s capital, Akaogi, was a better place to go in search of trade. It was the seat of Lord Tokitaka, master of Tanegashima, and the largest town on the island. This was arranged, and the foreign ship bearing the Portuguese strangers arrived at Akaogi on the twenty-seventh of the month.

  During their stay at Akaogi, the Portuguese introduced Lord Tokitaka and his retinue to a curious and wonderful device. It was “two or three feet long,” went one contemporary description, “straight on the outside with a passage inside, and made of a heavy substance. The inner passage runs through it although it is closed at the end. At its side there is an aperture which is the passageway for fire. Its shape defies comparison with anything I know. To use it, fill it with powder and small lead pellets. Set up a small white target on a bank. Grip the object in your hand, compose your body, and closing one eye, apply fire to the aperture. Then the pellet hits the target squarely. The explosion is like lightning and the report like thunder. Bystanders must cover their ears.”

  It was of course a gun, in particular an arquebus, a lightweight form of matchlock musket that could be fired from the shoulder without need of the supporting rest that heavier muskets required. It consisted of an iron barrel set in a wooden stock, with an S-shaped brass serpentine affixed to the right side. Several feet of saltpeter-soaked wick, or “match,” were needed for the weapon to remain useable for any appreciable length of time, for example throughout the course of a battle. The arquebusier would thread one end of this match through the serpentine, light it, and keep it constantly smoldering; the rest he would wind around the stock of the weapon, or around his arm. When he wished to fire he raised the weapon to his shoulder, slid back the brass cover to expose the gunpowder, then took aim and pulled the trigger, sending the serpentine down into the firing pan like a bird pecking the ground. After a moment’s pause, the match glowing at the end of the serpentine would ignite the gunpowder, sending a lead bullet exploding out the end of the barrel with a tremendous kick and a cloud of black smoke.

  Lord Tokiaki was immensely impressed by this simple but highly effective instrument. Still communicating through the Chinese pirate Wu-feng by means of written characters, he asked the Portuguese traders to tell him its secret. “The secret,” came the reply, “is to put your mind aright and close one eye.”

  Tokiaki found this somewhat confusing. “The ancient sages have often taught how to set one’s mind aright,” he said. “If the mind is not set aright, there is no logic for what we say or do....However, will it not impair our vision for objects at a distance if we close an eye? Why should we close an eye?”

  To this the foreigner replied, “That is because concentration is important in everything. When one concentrates, a broad vision is not necessary. To close an eye is not to dim one’s eyesight but rather to project one’s concentration farther.”

  “That corresponds to what Lao Tzu has said,” replied the delighted Tokiaki. “‘Good sight means seeing what is very small.’”

  Disregarding the high price the Portuguese were asking for these wonderful weapons, Lord Tokiaki purchased two specimens and devoted his every waking hour to mastering their use. Soon he was able to hit the target almost every time. He also had one of his retainers learn from the barbarians how to prepare the powder mixture that was clearly so essential.

  Following the departure of the traders, Lord Tokiaki ordered his craftsmen to make copies of his two prized firearms. What they produced resembled the foreign weapons outwardly, but would not fire, for they did not know how to close the barrel at the weapon’s shoulder end. This problem was solved in the following year, 1544, when a second foreign ship arrived at Tanegashima. There was among the crew this time an ironworker whom Lord Tokiaki’s craftsmen sought out for advice; one story has it that a blacksmith even offered his daughter in exchange for lessons. In any event the problem of closing the end of the barrel was soon solved, and within little more than a year the Tanegashima craftsmen had produced twenty or more working copies of the original barbarian gun. Lord Tokiaki then set his retainers to work learning how to use them, until they too could to hit the target almost every time.[2]

  * * *

  These lightweight muskets introduced into Japan by Portuguese traders in 1543 were not the first firearms to arrive on those shores. A variety of gunpowder-based weapons had already been imported from China, the birthplace of gunpowder, over the previous two centuries, first bombs and flame-spewing tubes, then cannons, and finally handheld guns. None of these Chinese imports, however, were ever widely used by the Japanese in warfare, for they were too crude and clumsy and ineffective to rival the bow and arrow, sword, and spear. The amazement that Lord Tokiaki and the people of Tanegashima evinced at their first sight of a Portuguese musket was therefore probably more a reflection of the isolation of their small island than of the actual state of knowledge then prevailing in Japan. To the more worldly leaders on the main islands, the musket would have seemed a more familiar weapon, an improvement on existing technology that transformed the handheld gun from an interesting but impractical oddity into an effective killing machine.[3]

  Within a few years of its arrival on Lord Tokiaki’s remote southern island, the technology to manufacture Portuguese muskets, referred to at first as tanegashima, spread to the main island of Kyushu, where a number of gunsmiths who had gained reputations for themselves opened “schools” and began training apprentices. These apprentices then moved elsewhere to open businesses of their own, crafting muskets in the distinctive style of their master—the same design, the same weight, the same caliber. In this way gunsmithing shops and factories spread all across Kyushu and then onto Honshu, where Sakai, near Osaka, and Kunitomo, just south of present-day Tokyo, became major production centers.[4]

  By the 1560s muskets were being turned out throughout most of Japan at a rate of at least several thousand per year. These weapons were as good as those being manufactured in Europe at that time and had the important advantage of greater standardization. In Europe there was virtually no standardization in the caliber of firearms; each gun needed its own bullet mold. This meant that if a soldier ran out of bullets in the heat of battle or if his little bag of lead slugs slipped from his belt and was lost, his weapon was rendered useless. He could not borrow bullets from a fellow soldier, for they would not fit his barrel. Nor could he run to a nearby supply wagon and grab a handful. In Japan the existence of gunsmithing schools did much to alleviate this problem. The different schools produced guns of widely varying caliber,[5] so it was not possible to equip an entire army with one standard weapon. But it was possible to equip a smaller corps of men with guns of a standard caliber simply by purchasing weapons from the same factory, and thus from the same school. This increased the utility of the Japanese musket and made the men who wielded them that much more effective.[6]

  * * *

  The first Portuguese muskets arrived in Japan during a time that Japanese familiar with Chinese history called sengoku, “the age of warring states,” after the period of civil war preceding China’s own emergence as a single, unified state some seventeen hundred years before. It was a 130-year period, from the 1460s until 1590, when the entire country was in constant upheaval.

  Sengoku was caused fundamentally by a lack of central authority. It was a problem with roots extending back into the twelfth century, when the emperor in Kyoto began to slip from his position of undisputed power. A line of military dictators known as shogun arose to fill the resulting power vacuum. At first they governed the country under the ostensible authority of the emperor. By the early thirteenth century, however, the imperial throne had become so powerless that even this pretense was dropped, and the shogun’s capital in Kamakura became the real seat of government.

  In 1333 the Kamakura shogunate, weakened by its fight against the invading Mongol armies of Kublai Khan, fell to a new line of military dictators known collectively as the Ashikaga shoguns. The Ashikaga, never very strong to begin w
ith, would undergo a slow decline over the next hundred years. This probably explains why the third shogun in the line, Ashikaga Yoshimitsu, resumed Japanese relations with China after a long period of quiescence by sending a tribute mission to the court in Beijing in 1401. The title “King of Japan” that the Ming emperor bestowed upon him lent authority to the Ashikaga’s shaky rule, and the substantial income derived from the de facto trade that occurred during tribute missions provided much-needed wealth for maintaining armies, supporting regal lifestyles, and running the country.

  But even this was not enough for the Ashikaga shoguns. Their decline was inexorable. By the early sixteenth century they no longer had the military power or financial clout to effectively control the country. And so there arose yet another power vacuum in Japan. But this time there was no one to fill it.

  The inevitable result was civil war. With neither the shogun nor the emperor able to guarantee property rights or the rule of law, ambitious men began to take charge. The sixteenth century opened with hundreds of regional lords and small groups all vying for each other’s territory and all arming to protect their own. Slowly, through conquest and the formation of alliances, these factions began to coalesce. By the middle of the sixteenth century the entire nation was in the hands of feuding war lords called daimyo, each holding his own private domain, none beholden to any central authority.

  It was at this time that the musket first appeared in Japan. Prior to this, warfare not just in Japan but in the Western world as well had remained substantially unchanged for nearly two thousand years, each generation going to battle with essentially the same bows and swords and arrows and spears. Indeed, as military historian Gwynne Dyer has observed, “competent professional armies chosen at random from anywhere between 500 B.C. and A.D. 1500 would stand a roughly equal chance in battle against each other—and that span of years could probably be pushed all the way back to around 1500 B.C. (the time of Megiddo) if the earlier armies were allowed to exchange their bronze weapons for iron ones.”[7] The introduction of the musket into sengoku Japan challenged and ultimately shattered this longstanding equilibrium. To survive the Darwinian rigors of the age required absolute pragmatism on the part of every daimyo intent upon survival, a determination to use any and every means at his disposal to crush the enemy and take his land before being similarly crushed in return. The musket’s value as a killing machine was therefore quickly recognized. Muskets were not expensive to produce; the more affluent daimyo could afford to have them turned out by the thousands. They did not require carefully crafted arrows, only simple lead balls. Their range and striking power was also superior to those of any traditional weapon. A musket, for example, could lob a slug nearly half a kilometer, compared to a maximum range of 380 meters for the heaviest—and most difficult to use—Japanese composite bow; at the closer distances at which most battles were fought, it could pierce iron armor that an arrow could only scratch. Finally, and most important, a musket was easy to use. This more than made up for its major weakness, its slow rate of fire. Even with practice it took nearly a minute to load and fire a musket, a period of time that would be only marginally reduced by the later introduction of pre-measured powder charges. A skilled archer, in contrast, could fire at least six well-aimed arrows in a minute. Skilled archers, however, took many years to train, they needed great muscular strength to wield the heaviest and in turn most dangerous bows, and they were therefore rare and expensive in sengoku Japan. The skills necessary to handle a musket, on the other hand, could be taught to anyone in just a few weeks. Adding a corps of musketeers to one’s army was thus considerably more cost- and time-effective than adding a corps of archers. All one needed was the cash to buy the weapons and a supply of able-bodied men.[8]

  These various practical advantages would make the musket a key weapon in the latter part of the sengoku era, when it would have a significant effect on the course of the history of Japan. Had the nation’s daimyo been confined to the traditional weapons of sword and spear and bow, the sengoku period would very likely have dragged on for much longer than it did. The introduction of the musket into Japanese warfare ensured that this did not occur. It gave a significant advantage to those daimyo who embraced it, doomed their less foresighted rivals, and ultimately hastened the advent of national unification.

  One such daimyo who recognized the importance of the musket early on was Oda Nobunaga. He was a violent individual reportedly from the day he was born in 1534, biting the nipples of every wet nurse employed to suckle him. Upon his father’s death in 1551, Nobunaga inherited a small, ill-defined domain in Owari Province on central Honshu, near the present-day city of Nagoya, plus a few tenuous alliances with neighboring daimyo that soon fell apart. Almost from the start the twenty-year-old warlord found his diminutive domain under attack. For the next several years Nobunaga managed to keep the predators at bay while he moved against rival factions of his own Oda house to bring all of Owari Province under his sway. Then he turned his attention outward.

  His first great victory came in 1560. Imagawa Yoshimoto, a much more powerful daimyo than Nobunaga with territory stretching across three provinces to the east, had long had his eye on Oda land. In 1554 and again in 1558 he sent small forces into Owari that Nobunaga managed to beat back. In 1560 Imagawa returned to finish the job, this time at the head of a forty thousand-man army. Nobunaga, with just two thousand men under his command, wisely chose not to meet this superior force in the traditional way. Instead he ambushed the invaders during a blinding downpour, when they were totally off guard and unable to see how small his army was. The strategy succeeded. The Imagawa army was put to flight, and Imagawa Yoshimoto himself was killed.

  The tide was now turning for Oda Nobunaga. In 1564 he took complete control of former Imagawa holdings in the provinces of Mikawa, Totomi, and Suruga after Imagawa Yoshimoto’s heir fled to a monastery. The Saito family fell in 1567, and with it the province of Mino to the north. Then came parts of Omi, Ise, and Iga. In 1568 Nobunaga entered Kyoto, deposed the puppet Ashikaga shogun supported by his rivals, and installed his own, Ashikaga Yoshiaki. When Yoshiaki rebelled against his benefactor’s heavy hand and tried to form an alliance against him, Nobunaga drove him into exile and brought the Ashikaga shogunate to an end. In the 1570s Kawachi Province fell to him, then the rest of Omi. Then Setsu. Kai. Echizen. Noto. Hida. Etchu. Shinano. Wakasa. By 1582, when he was assassinated by one of his own vassals, Oda Nobunaga controlled all or portions of thirty-one of Japan’s sixty-six provinces and roughly one-third of its land mass.

  Why was Oda Nobunaga such a successful conqueror? Because he was unconventional. To begin with, he did not rely on traditional samurai armies, mounted on costly horses, wielding expensive swords and wearing fancy lacquered armor. Instead he based his army upon the lowly ashigaru, the foot soldier. They could be easily recruited from the peasantry, they were cheap to arm, and they were easy to train. Second, Nobunaga’s forces were highly mobile. By improving roads, building bridges, and installing troop-ferrying ships on Lake Biwa, Nobunaga was able to move his armies around central Honshu with a speed that confounded his enemies. He also embraced the new technology of the musket. He started with an arsenal of five hundred weapons in the early 1550s. By 1575 he had ten thousand, enough to rival any daimyo. He gained this technological upper hand by capturing the two main centers of firearms production on Honshu, Sakai in 1569 and Kunitomo in 1570. After that most of the muskets produced outside Kyushu and its offshore island of Tanegashima came to him, along with the lion’s share of the gunpowder. The advantage of possessing all these muskets would become glaringly apparent in the celebrated Battle of Nagashino in 1575, when three thousand of Nobunaga’s musketeers effectively destroyed the army of Takeda Katsuyori with withering volley fire from behind the protection of a wooden palisade. When the battle was over, ten thousand of Takeda’s men—sixty-seven percent of his entire army—lay dead in the field, and with them many of the traditional notions of warfare in Japan.


  One final factor contributed to Oda Nobunga’s success: he was ruthless. In his private life he was a man of refined tastes. He was, for example, an avid practitioner of the art of tea, and considered the right to hold a private tea ceremony the greatest honor he could bestow upon a vassal. In his battles and political machinations, however, Nobunaga cast aside all niceties. Conquest was his goal, and he was prepared to do whatever was necessary to achieve it. His early campaigns to unite the Oda house and win control of his home province of Owari resulted in the deaths of a number of his own family members. In 1565 he confirmed an alliance with the Asai family by offering his sister in marriage. When this alliance crumbled six years later, family ties did not prevent Nobunaga from slaughtering his in-laws. In his 1571 campaign against the heavily armed Buddhist stronghold on Mount Hiei, countless monks were slain and the entire monastery complex, including shrines, was burnt to the ground. After his campaign in Echizen Province he wrote, “There are so many corpses in Fuchu that there is no room for more.”[9] It would be wrong to depict Nobunaga’s brutality as differing in kind from that of rival daimyo. He was just better at it.

  Oda Nobunaga’s ultimate goal was to bring all of Japan under his power. This was the case from at least 1567, when he began using a personal seal bearing the maxim tenka fuchu, “the realm subjected to military power.” His method of national unification, however, was slow and painful, for it ensured resistance at almost every step. For most of Nobunaga’s enemies, to capitulate without a fight meant losing everything, except perhaps their lives. Most chose to fight. Had Nobunaga lived, therefore, it was by no means certain that he would have succeeded in unifying the country, for a number of very formidable daimyo still stood in his way. Even if he had gone on to win ultimate hegemony over all Japan, it would likely have taken him many more years. That the task was accomplished in only nine years was due to the very different unification strategy pursued by his successor, Toyotomi Hideyoshi.