Ii Naomasa: The Red Guards Who Helped Build Tokugawa Power

Ii Naomasa (井伊直政, 1561–1602) became one of Tokugawa Ieyasu’s most trusted commanders during the final decades of Japan’s Sengoku, or Warring States, age. He is remembered for the red-lacquered armor of his troops, his forceful presence in campaigns such as Nagakute and Sekigahara, and the foundations he laid for the Ii family’s long rule in Hikone. His career was brief, but it joined the unsettled world of rival warlords to the new political order that followed.

Naomasa’s story is often told through a vivid image: a commander in crimson armor riding at the head of the Tokugawa vanguard. That picture is compelling, but his legacy was larger than a striking uniform or a battlefield nickname. He was a young survivor of a vulnerable local house, a disciplined military leader, a political beneficiary of Ieyasu’s victory, and the first head of a family whose influence endured for generations.

A young Ii heir in a dangerous age

Naomasa was born in 1561 into the Ii family, a warrior house based in Iinoya in Tōtōmi Province, in what is now Shizuoka Prefecture. The family’s position was shaped by its powerful neighbors. For a time, the Ii were tied to the Imagawa, whose lands stretched across parts of eastern Japan. The balance of power shifted sharply after Imagawa Yoshimoto was killed at Okehazama in 1560, and local families had to navigate the changing fortunes of the Imagawa, the Tokugawa, and the Oda.

Naomasa’s father, Ii Naochika, died when the boy was still very young. Later accounts describe suspicion and political danger around the Ii household, but the details of his childhood are not equally clear in every source. What is clear is that Naomasa came of age in a period when a family’s survival could depend on careful alliances as much as on fighting skill. The experience helps explain why his later career was inseparable from the patronage of Tokugawa Ieyasu.

The Hikone Castle Museum dates Naomasa’s birth to 1561 and records that he became Ieyasu’s vassal at about fifteen. Its collection describes him as a major contributor to Ieyasu’s establishment of the shogunate and as the first head of the Ii family whose work laid the foundations for Hikone’s later prosperity. Those points give a useful frame for his life: Naomasa was not simply a battlefield celebrity, but a retainer whose rise depended on trust, service, and rewards that could be passed on to his house.

For a young samurai, service in a great lord’s household offered both opportunity and risk. A retainer might gain land, status, and command, but those rewards came through loyalty tested in campaigns and political crises. Naomasa’s entry into Ieyasu’s service placed him within a rising military organization. The Tokugawa had to survive the competing ambitions of the Oda, Toyotomi, and other regional powers before it could govern a unified country. His future therefore depended on proving himself within an army that was still being built.

From household retainer to Tokugawa commander

Naomasa rose through the Tokugawa ranks during the 1570s and 1580s, a period when Ieyasu was expanding his reach and adapting to new alliances. The relationship between lord and retainer was personal as well as institutional. Ieyasu needed commanders who could lead men in the field, represent his authority, and carry out assignments that connected military action to the redistribution of land and influence.

Naomasa’s reputation grew alongside the Tokugawa cause. He served in campaigns that tested the clan’s capacity to move troops, coordinate allies, and answer threats across central Japan. His later prominence should not obscure the gradual nature of this rise. Rather than appearing fully formed as the “Red Devil” of popular retellings, he built authority through repeated service in a world where skill, discipline, and a patron’s confidence reinforced one another.

His proximity to Ieyasu also helps explain why his career is often discussed alongside other famous Tokugawa commanders. Tokugawa Ieyasu depended on a circle of capable retainers, including Naomasa, Honda Tadakatsu, Sakakibara Yasumasa, and Sakai Tadatsugu. Later writers grouped several of them as the Tokugawa “Four Heavenly Kings,” a memorable label that reflects their symbolic status as well as their military roles. Naomasa’s path differed from that of Honda Tadakatsu, whose career became famous for an almost legendary record of surviving battles without serious injury. Naomasa, by contrast, was repeatedly associated with forward action and the physical cost of war.

The distinction matters because samurai reputations were built after the fact as well as during a person’s life. A retainer’s actions could be remembered in family records, painted screens, military tales, and later popular culture. Each source had its purpose: a family archive could preserve service, a screen could display achievement, and a modern story could turn a complex career into a single dramatic image. Reading Naomasa’s story means holding those layers together without mistaking any one of them for the whole life.

Nagakute and the making of a visible force

One of Naomasa’s best-known early tests came in 1584, during the Komaki–Nagakute campaign. The conflict brought Ieyasu into opposition with Toyotomi Hideyoshi, who was consolidating power after the death of Oda Nobunaga. Naomasa is associated in later accounts with leading a large contingent of matchlock troops at Nagakute. Matchlocks had become an important part of Japanese warfare, and commanders had to combine firearms with movement, protection, and close-combat units.

Descriptions often give Naomasa a force of roughly three thousand gunners. Numbers in accounts of early modern battles can vary, so it is best to treat a precise figure cautiously. The larger point is that Naomasa was entrusted with an organized body of troops and that his performance helped distinguish him among Ieyasu’s commanders. This was not simply a matter of personal bravery. It required officers to maintain order, direct volleys, and keep formations effective while the battle shifted.

The image of a red-armored commander among gunmen also illustrates how warfare in the late sixteenth century was changing. The samurai ideal of mounted combat remained powerful, but armies increasingly relied on coordinated groups of foot soldiers, archers, spearmen, and matchlock users. A leader’s job was to make these units work together. Naomasa’s later reputation for boldness sits alongside this more practical side of command: building a force that could be recognized, directed, and deployed.

Why the Ii troops wore red

The red armor associated with Naomasa’s men is called akazonae, literally a red equipment or red armor formation. The Hikone Castle Museum describes the Ii family’s troops as “red guards,” known for red-lacquered suits of armor worn from the lord down to ordinary soldiers. That broad visual uniformity made the force distinctive in battle paintings and remains one of the clearest ways the Ii family is recognized today.

Color on the battlefield could carry several kinds of meaning. Matching armor and banners helped distinguish one contingent from another in the smoke, dust, and confusion of a battle. It also made a lord’s force visually memorable. Red lacquer was costly and labor-intensive, so a coordinated red-armored corps communicated resources and status as well as tactical identity. It could strengthen morale among the troops and announce the presence of a powerful unit to allies and opponents.

Modern stories sometimes call Naomasa’s troops the “Red Devils.” The phrase captures the fearsome image that later generations attached to them, but the more grounded historical term is the Ii red guards or akazonae. A vivid nickname can help readers remember a commander, yet it can also turn the men who served under him into a legend rather than a military organization. They were retainers and soldiers, equipped and trained within the Tokugawa order, and their red armor became part of that order’s public identity.

The color’s legacy continued long after Naomasa’s lifetime. The Hikone Castle Museum’s collection preserves the Ii family’s association with red armor and displays examples of equipment connected with the house. A suit of armor in a collection can illuminate materials, craft, and the way a family remembered its past. It cannot, by itself, prove that every surviving piece was worn by Naomasa in a particular battle. Museum descriptions therefore distinguish between armor known to be associated with the Ii family and pieces believed to have been worn by a specific person.

Sekigahara: a victory with a lasting cost

In 1600, the conflict that would decide who held national power reached a climax at Sekigahara. Tokugawa Ieyasu’s Eastern Army faced a coalition led by Ishida Mitsunari, whose forces supported the Toyotomi government. The battle took place in Mino Province, along the Nakasendō route linking eastern and western Japan. The victory transformed Ieyasu’s position and set the stage for the shogunate he would establish in 1603.

Naomasa’s red-armored troops fought on the Tokugawa side. The Hikone Castle Museum’s six-panel screen of the battle places the Ii warriors in distinctive red armor near the Tokugawa action, with Naomasa leading them. The screen is a nineteenth-century copy of an earlier work, and the museum notes that names of Ii retainers were added and corrected when the copy was made to commemorate their achievements. It is both a depiction of a pivotal battle and an example of how the Ii family presented its own history.

Accounts of the fighting describe Naomasa pursuing Shimazu Yoshihiro’s retreating force late in the battle. A shot struck him in the arm and knocked him from his horse. The U.S. National Park Service’s account of Sekigahara also records the wound during the Shimazu retreat. The episode is often framed as a moment of conspicuous daring, but it should be understood in the brutal context of a battle in which commanders and ordinary soldiers were exposed to gunfire and close combat alike.

The injury did not end Naomasa’s political importance, but it affected the final years of his life. He died in 1602, two years after the battle, at the age of forty-one by Western reckoning. Some accounts attribute his death to complications from the Sekigahara wound; the Hikone city history presents that as the cause. As with many early modern deaths, the exact medical details are difficult to reconstruct. What is certain is that Naomasa did not live to see the full development of the order his service had helped create.

Sekigahara also changed the scale of his responsibilities. Ieyasu rewarded Naomasa with Sawayama Castle and made him lord of the surrounding territory. The award reflected military achievement, but it also placed him in a strategic position in Ōmi, near Lake Biwa and on routes connecting Kyoto with eastern Japan. Naomasa’s work now involved holding land, managing retainers, and establishing the authority of a new domain as well as commanding in the field.

Sawayama and the foundations of Hikone

Sawayama Castle gave Naomasa a strong base in Ōmi Province, but it was not the final center of the Ii family. The strategic location of the region mattered to the Tokugawa government. The Japan Tourism Agency explains that Hikone domain was established in 1600 as Naomasa’s fief and that the area’s agricultural wealth, position beside Lake Biwa, and place on the Nakasendō made it commercially and militarily significant.

Naomasa’s assignment at Sawayama should not be confused with building the present Hikone Castle. That work began after his death. In 1603, Tokugawa Ieyasu selected a new site on Mount Hikone, and construction began in 1604 under Naomasa’s successor, his son Naotsugu. The Japan Tourism Agency notes that the castle’s main parts were completed in 1607 and that the full complex, including the outer defenses, was finished in 1622. Hikone’s official history recounts how materials from Sawayama and nearby sites were reused in the new project.

This distinction gives Naomasa a different kind of legacy. He was the first lord of the domain that would become closely identified with Hikone, but later generations shaped the castle town and its institutions. Naomasa’s role was foundational: he secured the family’s position, gained a domain, and left his heirs a place within the Tokugawa political system. The castle that visitors see today belongs to the story his son and successors carried forward.

The family’s rise also shows how the Tokugawa state governed. A domain was not simply a private estate. Daimyo were expected to provide military support, manage land and revenues, and maintain obligations to the shogunate. The Ii house’s favored status brought prestige and responsibility. Much later, members of the family would occupy senior political offices, including the position of tairō, or chief elder, at the shogun’s council. That later influence began with the rewards and connections Naomasa secured during Ieyasu’s campaigns.

A short life and a complicated inheritance

Naomasa’s wound and early death make his story feel unfinished. He died before the Tokugawa order had fully settled and before the Ii family’s new domain had taken shape around Hikone. His sons Naotsugu and Naotaka inherited the task of preserving the house’s position. Their succession was not automatic in the modern sense: a family needed the shogunate’s recognition, and each generation had to show that it could meet the duties attached to its land.

In popular retellings, Naomasa is often set beside Honda Tadakatsu as his opposite: one commander famously wounded, the other celebrated for surviving many battles. The contrast is neat, but it simplifies two long careers and the varied experiences of the men who fought in them. Naomasa’s injury does not make him reckless by definition, and Tadakatsu’s reputation for survival does not mean warfare was safe for him or his soldiers. These comparisons are most useful when they lead back to the different roles and risks inside Ieyasu’s army.

Naomasa also demonstrates how quickly a warrior’s identity could change. As a child, he belonged to a local family whose fortunes were exposed to larger powers. As a young man, he entered a rising lord’s service. At Sekigahara, he commanded a unit that became a visual marker of the Tokugawa victory. After the battle, he became a domain lord. Each role involved a different kind of authority, and his ability to move among them helps explain why Ieyasu valued him.

The armor, the image, and the evidence

Today, the strongest public image of Naomasa is still the red armor. The color makes a useful entry point into his story because it connects material culture to military organization. Armor was protective equipment, but it also marked rank, household, and allegiance. A force that presented itself consistently could be seen as a unit and remembered as a unit. In that sense, the Ii red guards made the power of a local house visible to a much wider audience.

Collections and displays at the Hikone Castle Museum help visitors look beyond the legend. The museum’s portrait identifies Naomasa as the first lord of Hikone domain. Its battle screen shows the Ii contingent within the larger Tokugawa army, while the armor collection connects later generations to the house’s martial identity. Such objects do not answer every question about the past, but they make the questions more precise: which piece belongs to which period, what can an image reliably show, and how did a family choose to remember its service?

It is also helpful to distinguish what the evidence says from what later storytelling adds. The dates of Naomasa’s life and his place in the Ii family are recorded by the Hikone Castle Museum. The museum’s screen supports the red armor association and his leading role in the Ii contingent at Sekigahara. The National Park Service account describes the wound he suffered during the Shimazu retreat. The Japan Tourism Agency and the official Hikone history trace the domain and castle’s development after 1600. Those sources together make a fuller picture than a nickname alone can provide.

Why Ii Naomasa still matters

Ii Naomasa matters because his life connects three turning points: the survival of a local warrior family, the military success of Tokugawa Ieyasu, and the creation of a durable domain in Ōmi. His red-armored troops made him memorable, but his political legacy came from service that extended beyond one battlefield. He helped transform a victory into a territorial settlement and a family position that endured well into the Edo period.

His story is also a reminder that the end of the Sengoku era was not a clean break from war to peace. The Tokugawa shogunate emerged through conflict, reward, and the careful placement of loyal houses. Naomasa fought in that process and was injured by it. He died before the new order fully matured, but the Ii domain carried his name and service into a future he could not see.

When the red armor appears in a painting or museum gallery, it can be read as more than a dramatic costume. It speaks of a commander’s visibility, a family’s identity, the work of soldiers in formation, and the way the Tokugawa victory was preserved in memory. That combination of battlefield record and later remembrance is what keeps Naomasa’s brief career compelling.