The Three Unifiers of Sengoku Era Japan

The Three Unifiers of Sengoku Era Japan


Few civilizations escape periods of chaos and upheaval.  For the Japanese, the Sengoku Era (1467-1603), also referred to as the Warring States Period was their age of turmoil. This essay explores the roots of the Sengoku period and the three men who emerged to restore a sense of political, economic, and social calm throughout the realm.

The Sengoku Ordeal

Since Minamoto Yoritomo was given the title seii tai-shogun (Japan’s leading military figure) in 1192, Japan functioned as a semi-bicameral political state. The emperor, which legitimized the shogun’s rule by appointing each successive military ruler, lived in Kyoto with other aristocratic families. The shogun and his close advisers chose an area to establish their geographical headquarters, which became known as the bakufu or the tent government. The Minamoto shogunate chose the beautiful setting of Kamakura as its home.  The emperor reigned but did not rule; it was the shogun and his deputies that governed Japan.

By 1333 the Minamoto bakufu had grown weak and the expenses related to defending Japan against Mongol invasions (1274, 1281) emptied the bakufu’s coffers.  Cousins of the Minamoto shogun (all subsequent shoguns had to be related to Yoritomo) the Ashikaga clan established the second shogunate rule, the Ashikaga bakufu (1336-1573)and placed its headquarters in Kyoto’s neighboring town of Muromachi. From the outset, the Ashikaga had multiple challenges of trying to keep unity throughout Japan.  Upstart emperors who wanted greater say in the running of their realm had to be quieted while bakufu-appointed military governors faced the dilemma of deputies carving out independent fiefs throughout Japan.

As each decade passed, imperial and shogunate power and  authority waned. Jizamurai—­samurai who lived within villages—farmed during planting and harvesting season and fought during the other parts of the year.  The bakufu tried to keep the centuries-long political system in place by appointing military governors, also known as shugo or daimyo to keep peace throughout Japan and provide taxes for the emperor and bakufu. These daimyo delegated authority to their retainer samurai and made some of them deputies (jito). But chaos prevailed through the first half of the sixteenth century.  Jito began to break free from their overlords and farmers were brought into the fray as huge armies emerged to help the upstart jito and daimyo fight for control of the land.

The Japanese worldview which was an amalgamation of Confucian, Buddhist, and Shinto beliefs emphasized a schematized social system where loyalty, deference to authority, and a rigid class system kept Japan in relative peace and prosperity for close to a millennium. But everything seemed to have changed during the Ashikaga bakufu. Japan’s sixteenth century moniker was gekokujo jidai “mastery of the high by the low.” It seemed wherever anyone turned, rebellion and deference to authority was replaced by Machiavellian pragmatism.

To add fuel to the fire of chaos, it was in the mid-sixteenth century that Westerners, in the form of Portuguese traders and Jesuit priests, entered Japan. Guns and cannons first brought by the Portuguese were duplicated in mass by Japanese entrepreneurial daimyo and metal workers. These guns and cannons spurred daimyo and jito to establish castles as defense fortresses against Japan’s nascent weaponry. The Portuguese were astounded at the lack of loyalty and the ubiquitous betrayals between jito and daimyo.  It seemed that everyone, including farming villages, chose to follow whoever promised the lowest taxes along with the maximum protection. War and plunder characterized both the countryside and the imperial capital. While the emperor and shogun still held their titles and positions, they were powerless against the tide and momentum of civil wars across the domains. The situation was akin to the British tale of Humpty Dumpty, the English egg fallen off a wall and scattered into hundreds of pieces. There were not enough imperial officials and bakufu samurai to put Japan back together again. And then three men changed everything.

The Three Unifiers

Oda Nobunaga, Toyotomi Hideyoshi, and Tokugawa Ieyasu (following the Japanese pattern of the surname coming before the given name) were all samurai from central Honshu. But that’s about where their similarities end. Their personalities and careers are contrasted by the following two anecdotes. A story is told that there was a bird that refused to sing. Nobunaga’s response was to warn the bird, “Sing or I’ll kill
you.” Hideyoshi coaxed the bird by saying “I’ll teach you to sing.” Meanwhile, Ieyasu sat back and thought “I’ll wait for the bird to sing.”  Another tale explains the pattern of how these three reunified Japan from a culinary perspective: Nobunaga kneaded the dough; Hideyoshi baked the pie; and Ieyasu ate the pie. The following paragraphs flesh out the meaning of these apocryphal stories.

Oda Nobunaga (1534-1582)

Oda Nobunaga’s father was a deputy for a daimyo and was given responsibility for portions of the Owari domain. This was a province  made up of eight districts and was one of the more productive portions of Japan for the dietary staple of rice. In 1551, Oda Nobunaga inherited the portion of land that his father protected and he began to extend his hegemony to other districts within Owari. As noted above, this was the common practice of the day. In a world of gekokuju jidai, all that was needed to extend one’s authority was opportunity, vision, and bravery. Nobunaga had all of these items in his toolkit. Like other opportunists that extended their authority, Nobunaga needed a big break to attract masterless samurai and farming villages. That small marvel came in 1560 when a leading daimyo, Imagawa Yoshimoto from the neighboring Suruga Province led an army of 40,000 to squash the upstart Oda Nobunaga. With just 2,000 samurai, Nobunaga defeated Imagawa’s invading force and in the battle Imagawa lost his life.

Nobunaga’s quickly followed up this victory by forging an alliance in 1562 with Tokugawa Ieyasu, the daimyo of Mikawa Province. Having secured his eastern flank, Nobunaga turned his attention to consolidating his hold on central Honshu. An early adopter of gun weaponry, Nobunaga established an armory at Sakai and successfully integrated these weapons in his battle plans.

Seeking greater legitimacy, Nobunaga marched into the imperial capital in 1568. Working together with the imperial and bakufu, Nobunaga maneuvered for Ashikaga Yoshiaki to be installed as the bakufu’s next shogun. Nobunaga planned to rule behind the scenes and simply use Yoshiaki as a political puppet. The plan went awry when Yoshiaki failed to defer to Nobunaga; subsequently, Nobunaga brought the Ashikaga shogunate to an end in 1573. Eschewing the need for bakufu authority, Nobunaga defeated six of the strongest military houses in western Honshu.

What struck the Europeans in Japan as most strange regarding Nobunaga’s military conquests was the lack of mercy shown to his enemies, especially the Buddhist monks. In a particular battle at Mount Hiei, over ten thousand Buddhist monks from the Tendai sect begged Nobunaga to accept gold from the institution rather than taking their lives. Nobunaga refused the overture and slaughtered the monks.

Nobunaga had ten major daimyo who reported to him and he often sought their advice. He was open to criticism from those close to him, and expected candor from his generals rather than patronizing acquiescence.

Between 1576 and 1579 Nobunaga lived in relative peace in a castle close to the imperial capital. He was not given the title of shogun, but was not bothered by this given his belief that brute power legitimizes authority. But in his rise to power he had to make difficult decisions that garnered him many enemies—even from within his own ranks.

One of his top generals, Akechi Mitsuhide held a grudge against Nobunaga due to Nobunaga’s role in the death of Akechi’s mother. In 1582 while Nobunaga was at a Kyoto Buddhist temple for a tea ceremony, he was caught by surprise when Akechi surrounded the temple to exact revenge against his master.  He set the temple on fire and Nobunaga along with his son died. Thus, the meteoric rise of the lowly jito from Owari came to a sudden ignoble end.

Nobunaga had accomplished a great deal. He began the process of unification, removed the Ashikiga shogunate, and established a modicum of order across Honshu. Yet, his legacy in Japanese history is mixed. Because he eschewed the Confucian values of deference based on filial relationships, and a ruler-subject bond, he is viewed as someone who did not follow the properdao or way prescribed to humans from heaven itself.

Toyotomi Hideyoshi (1536-1598)

Oda Nobunaga died without reunifying all of Japan. There were still independent domains scattered throughout Honshu (particularly the extreme eastern portion of the island) and Kyushu was dominated by two autonomous daimyos.  Furthermore, it was not clear as to who would take control of the lands and peoples that Nobunaga had managed to unite. Out of this chaos and potential dissolution of Nobunaga’s unification campaign emerged a most surprising leader who is considered one of the most important Japanese leaders in history.

Toyotomi Hideyoshi was the son of a low-ranking samurai in the Owari domain. When Hideyoshi was in his mid-teens he walked off the farm and sought attachment to an established or up-and-coming daimyo. He placed his bets on the rising star Oda Nobunaga. It was a good bet.  Starting out at the lowest level in Nobunaga’s retinue, Hideyoshi slowly rose in ranks, gaining the confidence of his master by his victories on the battlefield and unswerving loyalty. He became part of Nobunaga’s inner circle of military leaders, and at the time of Nobunaga’s assassination Hideyoshi was waging a brutal battle against the recalcitrant Mori house in the Bitchū Province, west of Kyoto.  Nobunaga’s death created a power vacuum, and while some of his generals quickly retreated to their home provinces, Hideyoshi marched toward Kyoto with the intention of killing his master’s assassin.  Hideyoshi’s troops caught up with Akechi’s army, and following a bloody battle Hideyoshi emerged victorious, brought Akechi’s corpse back to Kyoto, and took on the mantle of Nobunaga’s successor.

Building on Nobunaga’s military successes, Hideyoshi appreciated the power of diplomatic persuasion much more than his master did. He secured alliances through both diplomatic and military prowess during the first years following Nobunaga’s death. The two main holdouts were the Kyushu domains and the extreme eastern section of Honshu controlled by the Hojo House. With regard to the hinterlands of Kyushu, Hideyoshi adroitly sided with Kyushu’s Ōtomo Sōrin (a Christian Daimyo) against Satsuma, the leading domain on Kyushu. Following Hideyoshi/ Ōtomo‘s 1586 victory over Satsuma, Ōtomo submitted to Hideyoshi’s hegemonic rule over the Kyushu domains.

Finally, in 1590, four years following the battles in Kyushu, the Hōjō daimyo in the eastern portion of  Honshu was the final holdout against the full unification of Japan. Hōjō Ujimasa whose Odawara castle in Sagami Province appeared impregnable refused to acquiesce to Hideyoshi’s overtures for peace. In fact, it took a three-month siege for Hideyoshi’s army to finally capture the fortress. Hōjō Ujimasa might have imagined that he would receive mercy from Hideyoshi because the Satsuma daimyo had actually been given favorable terms following his defeat in Kyushu a few years earlier. But Hideyoshi became a bit more unpredictable with age and he ordered Hōjō to commit seppuku following the fall of Odawara.

As Hideyoshi’s steady hegemonic control of Japan continued, he established brilliant policies that transformed Japan and in many ways began to usher in a system that would stay in place until the end of the nineteenth century.  A primary concern for Hideyoshi was the elimination of large armies that had plagued Japan for decades during the Sengoku era.  He did this in two ways where everyone in Japan could feel somewhat good about these monumental shifts in Japan’s social history. He began his policies of peace by disarming the farmers. In 1588 Hideyoshi ordered that all weapons be taken away from farmers. It was called The Great Sword Hunt, and it effectively reduced Japan’s fighting population to the samurai class, which was around six percent of the population.  No longer could daimyo co-op farmers to serve as infantry soldiers, as farmers were prohibited from owning weapons. Some of the swords collected from the farmers were melted down and the metal used to form a large Buddha statue.

This weapons-control edict did not sit well with the farmers, but certainly the samurai and the Buddhist sangha (community/church) benefited from this. For the Buddhist leaders, they had a new statue in the Asuka-dera monastery in Nara. Samurai enjoyed the exclusive status of sword-carrying privilege throughout the realm. If one was wearing a sword, then everyone knew that individual was from the samurai class. The sword brought with it both status and privilege and now only the samurai could carry such a weapon. But not all was lost for the peasants.

On the heels of this famous sword hunt, Hideyoshi froze the social order. Broadly dividing Japan’s population into four classes: samurai, farmer, artisan and merchant, Hideyoshi decreed that these classes were fixed and prohibited movement from one class to another; as such, samurai were ordered to attach themselves to a particular daimyo and move away from the peasants. This affected tens of thousands of individuals who were known as jizamurai or “samurai of the land.” The jizamurai lived among the farmers and worked side-by-side commoners. With Hideyoshi’s new policy, however, samurai were, for the most part, detached from their farms and agrarian neighbors. This was to the advantage of the common folk because they were no longer intimidated by their military neighbors and were more free than ever to work the land.

Of even greater importance than the already-noted profound social changes, was  Hideyoshi’s order to conduct a national cadastral survey. In short, every inch of Japan’s agricultural land was measured in terms of just not geographical location but annual production. Rural lands were all placed in categories such as wet land, dry land, residence land and kitchen gardens. Rice paddies were labeled superior, medium and inferior based on farming records.  Following this massive undertaking, the government, now under the rule of Hideyoshi, issued documents to families who had worked that land for generations. Furthermore, each village was assessed a certain amount of annual tax (usually paid in rice) based on the cadastral survey.  The harvested rice was measured in terms of koku which was around 300 pounds each or about 5.1 bushels—enough to feed a person for a year.

The implications of this project were massive. Government officials knew how much annual revenue to expect and planned accordingly. Farmers knew how much they were to be taxed and their annual contribution to the village—tax was collected at the village level. This also led many farmers to seek ways to improve their harvests as they would not be penalized for growing more than the cadastral assessment—the tax was at a fixed amount.

Based on this survey, Hideyoshi divided the responsibility of ruling Japan to his generals. In addition to the geographical division of the land, Hideyoshi also noted how much koku each general should receive based on their domains. For example, while his top general, Tokugawa Ieyasu was given the eastern provinces to govern, he also knew that these provinces annually produced 2.4 million koku—which made him the highest “earning” general in the land. This fostered a sense of reciprocity and loyalty between Hideyoshi and his military governors.

During the last decade of his life, Hideyoshi veered away from his reliance on diplomacy and acted somewhat erratically. For example, while at times he appeared to appreciate the work of the Jesuits and Franciscans in Japan, he also ordered the execution of Catholic priests and Japanese Christians. This included the 1596 crucifixion of 26 Christians (nine priests and seventeen Japanese laymen) in Nagasaki.  Just one year earlier, Hideyoshi had his nephew (Toyotomi Hidetsugu) executed along with 31 of his family members. Hidetsugu was in line to take over after his uncle died, but Hideyoshi had a son in his old age and so he wanted to remove all potential rivals. For reasons that remain somewhat unclear, Hideyoshi also ordered that Japan conquer China. Thousands of samurai were sent to Korea as a stepping stone to China, but they found fierce resistance from Korean and Chinese soldiers and became bogged down in a somewhat senseless military campaign.

A bright spot for Hideyoshi in his final years was the birth of a long-hoped-for heir in 1593. Though he had united Japan, Hideyoshi did not have the pedigree to become shogun. His wife Yodo-dono was distantly related to the Minamoto house and so when she gave birth to Toyotomi Hideyori in 1593, there was an heir that had the bloodline to establish a new shogunate rule. In many ways, Hideyoshi set the table for a long and prosperous rule by his successor. Unfortunately, Hideyori was only five years old when Hideyoshi died in 1598 and Japan faced another crisis in leadership.

During his last days, Hideyoshi requested that his top five generals swear an oath of loyalty to his young son, Hideyori.  The five generals agreed to act as protectors for the Toyotomi heir until he was old enough to lead Japan and rule as a court-appointed shogun.  The five generals agreed to serve as regent to the boy as he lived with his mother in the Osaka Castle. Tokugawa Ieyasu, Hideyoshi’s most powerful ally and one of the generals who swore allegiance to Hideyori had different plans about who should take over a new unified Japan—namely, himself.

Tokugawa Ieyasu

In 1543 the Matsudaira House was jockeying for power in the very important province of Mikawa. With some of the best area for farming rice, multiple daimyo sought control of Mikawa. In 1543 Matsudaira Hirotada, the daimyo of a large portion of Mikawa welcomed a new son into the family, Matsudaira Takechiyo. He would not live to see his new son grow up as he died when Takechiyo was just six years old. Takechiyo’s turbulent childhood included being kidnapped and ransomed by rival daimyo and the concomitant diminution of the Matsudaira house’s fortunes. 

As a young man, Takechiyo exhibited leadership qualities to the point of inspiring the sagging spirits of samurai attached to the Matsudaira clan.  Takechiyo’s military victories across Mikawa were so impressive that in 1566 the emperor gave him the title of Mikawa no Kami or lord of Mikawa. The following year Takechiyo changed his surname and given name to Tokugawa Ieyasu.

Serving as an ally to Nobunaga and then Hideyoshi, Ieyasu became the dominant daimyo in Japan’s Kanto area in eastern Honshu.  He was given the village town of Edo which served as the Tokugawa house headquarters.  But following the 1598 death of Hideyoshi, he moved to Osaka and claimed that he was taking the lead in protecting Hideyoshi’s widow and the young heir, Hideyori. He also began sending letters to the various daimyo seeking their allegiance, which created deep resentment with Hideyoshi’s other generals. Those that were loyal to the Toyotomi family began to fear that Ieyasu was positioning himself to become shogun and rumblings of war again troubled the realm.

This rivalry was not only between the Toyotomi and Tokugawa factions but was also western versus eastern armies. The military showdown took place at Sekigahara on October 21, 1600 in one of the epic battles of Japan’s long history.  Throughout that fateful battle, the future of Japan was at stake as the conflict’s outcome was in doubt until the very end of the day. Tokugawa Ieyasu emerged victorious and used this military success to implement his rule in Japan.

Building off of Hideyoshi’s cadastral survey and the division of land based on rice production, Ieyasu stripped 87 daimyo of their domains.  Japan was divided up into hans (domains), each one had to produce at least 10,000 koku annually. In a very astute move, Ieyasu distributed governance of Japan’s land to three different types of daimyo (military governors).  About one third of Japan’s riches (rice) were put in the hands of the daimyo related to the Tokugawa house. The second group of daimyo were known as the fudai daimyo and those were the generals who allied with Ieyasu at the Battle of Sekigahara. Finally, land that annually yielded more than ten million koku was given to thetozama daimyo—or those that had not allied with the Tokugawa house.  This was one of many reasons that there was not a further rebellion against the Tokugawa clan.

In 1603 Tokugawa Ieyasu was given the title of seii tai-shogun by the emperor, meaning he was declared the realm’s top general. The policies that he, his son, and grandson put in place laid the foundation for one of the most remarkable periods in Japanese history. Known as Tokugawa Japan, also as Edo Japan, the period from 1600 to 1868 was one of great peace and moved Japan toward modernity. Historians often label the political paradigm the Tokugawa shoguns implemented as the Baku-Han system. Some of the more prominent features of this structure are noted below.

The Tokugawa house continued the practice of keeping the military headquarters (bakufu) separate from the imperial capital (Kyoto). The Tokguawa bakufu in Edo transformed the area from a fishing village to what some claim was the world’s largest city by 1700, with a population of over one million. Yet many have noted that while Tokugawa Japan experienced great peace and a sophisticated political system, it was not really a unified state. The realm was divided up into various domains that numbered almost 300 by the end of the Edo era.  Each domain, also known as a han, was controlled from a castle town where the military governor and his samurai retainers resided. Hans were semi-autonomous states enjoying their own economic and judicial systems. As noted earlier, most hans were ruled by daimyo not related to the Tokugawa family and these hans were not required to pay any taxes to the bakufu.

While many daimyo enjoyed semi-autonomous status, they were accountable for keeping their domain’s inhabitants safe and free from starvation. The bakufu had the authority to remove or transfer incompetent daimyo, and the military governors needed the shogun’s permission to marry. Daimyo were not allowed to expand their castle structure without permission from the daimyo. For long periods of Tokugawa Japan, the daimyo were also forced to keep their wife and first son in Edo in an almost hostage-type of arrangement. Furthermore, the daimyo were required to visit Edo regularly in a pattern that became known as sankin kotai, or alternate attendance. All of these rules helped to keep a balance of power and accountability throughout Tokugawa Japan.

Tokugawa Ieyasu differed from the first two unifiers in that he had many children. Just between 1557 and 1583 he sired ten children with five different women. He became a father for the last time in 1607 at the age of 64. With so many children, he was able to distribute authority and rule through his sons. In 1605, just two years after accepting the title of shogun, he resigned his position and it was passed on to his 26-year-old son, Hidetada. This astute move guaranteed that the Tokugawa rule would extend after Ieyasu passed from the scene. Nonetheless, Ieyasu continued to be the main authority of the bakufu until his death in 1616.

Between his 1605 resignation and his death in 1616, Ieyasu kept busy. He became one of the world’s richest men by monopolizing the mining industry in Japan. This was a period in China when the Ming dynasty was in its death throes and was desperately seeking Japanese imported silver to keep the system afloat. During the first decade of the seventeenth century it is estimated that up to one-third of the world’s silver came out of Japan, and much of it was sold to China, making Ieyasu extremely wealthy. Despite his enormous riches, Ieyasu preferred the simple life. His passions included the sport of hawking and he would take a simple lunch out with him on the many days that he spent absorbed in the sport. Though he was involved in over a dozen major battles, he turned in his older age toward a more completive life following the doctrines of both neo-Confucianism and the Tendai sect of Buddhism.

However, Ieyasu’s parting gift to his offspring and future Tokugawa shoguns was one of the more cruel acts he perpetrated. Hideyoshi’s son, Hideyori and his mother continued to dwell in safety at the Osaka Castle. There were many anti-Tokugawa officials and military leaders that continued to support the Toyotomi family with the hopes that Hideyori would one day supplant the Tokugawa house and establish a Toytomoi shogunate. Ieyasu was wary of this potential development and so in 1614 he gathered tens of thousands of samurai and marched to Osaka with the intention of eliminating the Toyotomi threat. In a somewhat surprising development, Ieyasu’s army lost the initial battle and he retreated back to eastern Honshu. Believing that Hideyori’s position was so secure in the Osaka Castle, Ieyasu bargained with the Toyotomi house, promising to cede portions of Japan to it in exchange for Hideyori removing the defenses around the Osaka Castle. Hideyori agreed to this plan, and the moats around the castle are filled in.  This spelled disaster for the Toyotomi family as Ieyasu almost immediately returned with his army to Osaka and on June 5, 1615 they broke through the castle. Despite pleas for mercy, Ieyasu made sure that Hideyori and his mother died in the battle. Part of this destruction of the Toyotomi family included a public decapitation of Hideyori’s eight-year-old son.

With the elimination of the Hideyori threat, Ieyasu believed that he had provided a bright future for the Tokugawa shoguns who would follow after him. On June 1, 1616, almost one year to the day after the fall of the Osaka Castle, Ieyasu died of congestive heart failure.


Following the chaos of the sixteenth-century warring states period, Japan’s reunification was a process that took almost half a century. It began with a Machiavellian-type leader, Oda Nobunaga. He spared no one who stood in his way, including the shogun and the Buddhist church. Perhaps it took such draconian measures to discourage the prevailing thought that loyalty to any authority was a thing of the past. Hideyoshi continued the work started by his lord but used diplomatic persuasion more than military might to bring Japan together. Hideyoshi also implemented social and land reforms that laid a foundation for Tokugawa Ieyasu to build upon. Finally, Ieyasu combined both the harsh rule of Nobunaga and the political acumen of Hideyoshi to establish the Tokugawa bakufu which led to almost three centuries of peace and economic stability throughout Japan.


Type,Article; Theme,Early Japan; Theme,History; Topic,Military; Topic,Politics; Topic,War & Conflict;
sengoku, japan, war, warring states, minamoto, yoritomo, shogun, daimyo, Oda Nobunaga, Toyotomi Hideyoshi, Tokugawa Ieyasu,war, Sengoku, government