[1568–1582] The Unification under Oda Nobunaga

We begin in the mid-16th century, a time of profound turmoil in Japan known as the Sengoku Jidai, the Age of Warring States. For over a hundred years, the land had been fractured, a chaotic mosaic of domains ruled by ambitious warlords called daimyō. The central authority of the Ashikaga shogunate had crumbled, leaving the shogun in Kyoto a mere puppet, and the divine Emperor a powerless, secluded figure. The countryside was a landscape of perpetual conflict. The air in many provinces tasted of ash from smoldering villages, and the rhythm of life was dictated not by the seasons, but by the marching of armies. Farmers, who made up over eighty percent of the population, planted their rice under the constant threat of being conscripted for battle or having their harvests seized by passing samurai. Society was rigidly stratified, but this era of chaos also presented a grim opportunity. A new maxim ruled the land: gekokujō, the low overthrowing the high. Loyalty was a commodity, and betrayal a common tool of advancement. In this crucible of fire and blood, a man would emerge from the minor province of Owari, a man who would burn away the old world to forge a new one. His name was Oda Nobunaga.

Oda Nobunaga was not what anyone expected. In his youth, he was known as the "Fool of Owari" for his bizarre behavior. He would wander the streets in outlandish, often Portuguese-inspired clothing, consorting with commoners and disregarding the stiff etiquette of the samurai class. But beneath this eccentric exterior was a mind of searing intelligence and radical vision. He saw a future that others could not. After inheriting his clan upon his father's sudden death, he systematically eliminated rivals within his own family and solidified his control over Owari province. His defining early victory came in 1560 at the Battle of Okehazama. Outnumbered nearly ten to one by the powerful warlord Imagawa Yoshimoto, Nobunaga launched a daring surprise attack during a thunderstorm. The storm masked the approach of his 3,000 soldiers, who descended upon the unsuspecting Imagawa camp, slaying the great daimyō himself. The victory was legendary, announcing Nobunaga's arrival on the national stage. It was a testament to his core principles: superior intelligence, decisive action, and a willingness to break every rule of conventional samurai warfare.

By 1568, Nobunaga’s ambition had grown far beyond the borders of his home province. He found a pretext for national power by championing Ashikaga Yoshiaki, a claimant to the shogunate. With his disciplined and well-equipped army, Nobunaga marched on the imperial capital of Kyoto. He met little resistance; many daimyō, weary of the chaos, either joined him or stood aside. By installing a new shogun, Nobunaga became the de facto ruler of central Japan. But his true genius lay in his embrace of new technology. While other samurai clans revered the bow and the sword, Nobunaga saw the future in the arquebus, a crude matchlock firearm introduced by Portuguese traders just a few decades earlier. He equipped a significant portion of his infantry with these weapons and, crucially, developed tactics to maximize their effectiveness. This revolution in warfare was unleashed in its full, terrifying fury at the Battle of Nagashino in 1575. Facing the fearsome Takeda clan, whose cavalry was considered the most powerful in all of Japan, Nobunaga did the unthinkable. He built long wooden palisades to protect his 3,000 arquebusiers. As the Takeda cavalry charged, they were met not with arrows, but with coordinated, rotating volleys of gunfire. The sound was deafening, the smoke choking. One rank fired while the others reloaded. The elite samurai riders and their mounts were torn apart, their traditional charge broken against a wall of lead and thunder. The age of the sword was ending; the age of the gun had begun.

Nobunaga’s methods for unification were as brutal as they were effective. He demanded absolute submission, and those who resisted were shown no mercy. His most infamous act came in 1571. The warrior monks of the Enryaku-ji monastery on Mount Hiei, a wealthy and politically powerful Buddhist sect, had defied him and allied with his enemies. Nobunaga's response was absolute. He surrounded the entire mountain complex and set it ablaze. His army was ordered to kill everyone they found—monks, lay-priests, women, and children. An estimated 3,000 to 4,000 people were slaughtered. The act horrified Japan and earned Nobunaga the moniker of "Dairokuten Maō," the Demon King of the Sixth Heaven. He intended it as a message: no institution, no matter how sacred, could stand in his way. Yet, this same ruthless conqueror was also a brilliant administrator and a patron of culture. He implemented "rakuichi rakuza" policies, which created free markets and abolished the monopolistic trade guilds that had stifled commerce for centuries. This stimulated the economy, funded his campaigns, and drew merchants and artisans to his domain. This vision was embodied in his magnificent Azuchi Castle, completed in 1579. Perched on a mountain overlooking Lake Biwa, it was unlike any fortress built before. Its seven-story keep soared into the sky, its interiors decorated with brilliant paintings by the master Kanō Eitoku. It was not just a military bastion but a luxurious palace designed to project overwhelming power and sophistication, a symbol of the new, unified Japan he was building.

By the summer of 1582, Oda Nobunaga stood at the zenith of his power. He controlled the thirty central provinces of Japan, the heartland of its political and economic life. The remaining rival clans in the west were on the verge of collapse. His goal of "Tenka Fubu"—unifying the realm by military force—was within his grasp. He was preparing to lead a campaign against the Mōri clan and had traveled to Kyoto, staying at a small temple called Honnō-ji with only a few dozen attendants and bodyguards. It was a moment of supreme confidence, which would prove to be his fatal error. One of his most trusted and capable generals, Akechi Mitsuhide, was supposed to be marching west to reinforce the front. But on the night of June 21st, under the cover of darkness, Mitsuhide gave a shocking order to his army of 13,000 men: "The enemy is at Honnō-ji!" His forces turned and marched not west, but east, back toward Kyoto. They surrounded the temple, their betrayal absolute and silent until the first volley of arrows and gunfire shattered the night. Nobunaga was completely taken by surprise. Awakened by the sounds of battle, he and his small retinue fought desperately against impossible odds. Wounded by a spear, Nobunaga, the great unifier who had burned and built his way across Japan, retreated into the temple's burning inner rooms. There, he committed seppuku, taking his own life to avoid the shame of capture. His body was consumed by the inferno, never to be found. The Demon King was dead.

The death of Oda Nobunaga sent shockwaves across the country, plunging it back into uncertainty. Akechi Mitsuhide’s betrayal earned him the title of "the thirteen-day shogun," as he was quickly defeated and killed by another of Nobunaga’s loyal retainers, a peasant-born general named Toyotomi Hideyoshi. The dream of unification did not die in the flames of Honnō-ji. Nobunaga had done the impossible: he had broken the back of the old feudal order. He had shattered the power of the Buddhist monasteries, revolutionized warfare, and created economic systems that enabled a centralized state. He was the first great hammer blow that cracked the bedrock of the Warring States period. It was left to his successors, first Hideyoshi and then the patient and cunning Tokugawa Ieyasu, to finish the work he had started. They built upon the foundations he laid, ultimately ushering in over 250 years of peace under the Tokugawa shogunate. Oda Nobunaga’s fourteen-year reign was a whirlwind of violence, genius, and ambition. He was a tyrant to his enemies and a visionary to his allies, a figure of profound contradiction whose brutal and brilliant legacy defined the end of one age and the violent birth of another.