The Battle of Sekigahara
The Sengoku period ended with the significant event known as the Battle of Sekigahara, which took place in Gifu Prefecture, Japan, on October 21, 1600. Tokugawa Ieyasu’s forces secured victory by vanquishing a coalition of clans loyal to Toyotomi, commanded by Ishida Mitsunari. Before and during the battle, numerous defections played a crucial role in securing Tokugawa’s triumph. This conflict is the largest in Japanese feudal history and has immense significance. The defeat of Toyotomi led to the establishment of the Tokugawa shogunate. Even though it took another three years for Ieyasu to consolidate his power fully, the Battle of Sekigahara is widely considered the unofficial inception of the Tokugawa shogunate.
Unifying Japan: Hideyoshi’s Rise
Toyotomi Hideyoshi, a prominent military leader serving under Oda Nobunaga, played a pivotal role in unifying Japan by defeating Shōgun Ashikaga Yoshiaki and ending the Ashikaga shogunate. However, his fortunes took a downturn when he was betrayed by Akechi Mitsuhide, leading to his tragic demise during the Honnō-ji Incident in 1582. Hideyoshi, driven by a desire for vengeance against those responsible for his master’s death, worked diligently to consolidate his authority over Japan, often relying on the support of his brother, Hidenaga.
Due to his modest background, Hideyoshi strategically formed alliances through marriage with noble women, ensuring his descendants would have prestigious family ties. His rule was characterized by a period of turbulence, exemplified by events such as the Siege of Odawara in 1590 and military campaigns in Korea, eroding the Toyotomi clan’s power. In 1595, Hideyoshi ordered the execution of Toyotomi Hidetsugu and his family, who had been designated to assume leadership after his passing.
Approaching his deathbed in 1598, Hideyoshi established a regency government, which left a void of leadership with no appointed shōgun overseeing the armies. During this uncertain time, the respected regent Maeda Toshiie, a neutral and stabilizing figure, managed to maintain peace for a time but, unfortunately, also passed away in 1599.
Emergence of Two Factions
Two prominent factions emerged in the later years of Hideyoshi’s rule and following his death. Tokugawa Ieyasu, a formidable figure within the regency government, garnered the support of many lords from eastern Japan. In contrast, loyalists of the Toyotomi clan and lords from western regions rallied behind Ishida Mitsunari. Periodically, tensions between these factions escalated into open conflicts, ultimately leading to the climactic Battle of Sekigahara in 1600.
Individuals such as Katō Kiyomasa and Fukushima Masanori publicly voiced criticism of the bureaucrats, particularly targeting Mitsunari and Konishi Yukinaga. Tokugawa Ieyasu seized this opportunity by recruiting these critics, redirecting their animosity to undermine the strength of the Toyotomi clan. Rumors were circulating that Ieyasu aspired to take up Hideyoshi’s legacy, resulting in accusations of unrest among former Toyotomi vassals. This unrest culminated in a conspiracy to assassinate Ieyasu, leading to the accusation and submission of many loyalists.
Uesugi Kagekatsu, one of Hideyoshi’s designated regents, openly challenged Ieyasu by fortifying his military forces. In response, Ieyasu’s chief advisor, Naoe Kanetsugu, mocked Ieyasu for what he perceived as abuses and violations of Hideyoshi’s directives. Consequently, Ieyasu led his supporters northward to confront the Uesugi clan, even though many were already besieging Hasedō. Recognizing the opportunity, Ishida Mitsunari allied to counter Ieyasu’s supporters.
Formation of the Western Army
During the Edo era, Ishida formed a coalition alongside Ōtani Yoshitsugu, Mashita Nagamori, and Ankokuji Ekei, giving rise to what would become known as the Western Army. Mōri Terumoto took control of Osaka Castle as their operational headquarters, capitalizing on the absence of most of Tokugawa’s forces, which were engaged in an attack against Uesugi. Ishida’s primary goal was to reinforce Mōri’s position at Osaka Castle, secure control over Kyoto, and challenge the Tokugawa. His initial target was Gifu Castle, which was then under the rule of Oda Hidenobu.
In response, Tokugawa Ieyasu led the Eastern Army, comprising 30,000 and 40,000 men, and divided his troops as they marched westward along the Tōkaidō route toward Osaka. The Tokugawa forces faced the challenge of having only two available roads leading to Gifu Castle. While Ieyasu advanced toward Gifu, Ishida Mitsunari encountered delays at Fushimi Castle, a midpoint between Osaka and Kyoto. Capturing Fushimi took Ishida ten days when Gifu Castle fell to the Tokugawa forces, prompting Ishida Mitsunari to retreat southward amidst the rain.
By mid-October 1600, Ishida Mitsunari and his troops had taken refuge at Ōgaki Castle. However, with Tokugawa’s army reaching Mino Akasaka, Ishida abandoned his position and marched toward Sekigahara. Despite the tactical advantages initially held by the Western Army, Ieyasu had established contact with numerous daimyō in the Western Army over several months, promising them land and leniency following the battle.
One of Mitsunari’s commanders, Miss Sakon, initially sought permission to engage the nearest Tokugawa troops but later clashed with Honda Tadakatsu at the Battle of Kuisegawa. This encounter resulted in significant losses for the Eastern Army, forcing them to withdraw from Mino Akasaka territory to Sekigahara. Mitsunari then ordered his forces to surround Ieyasu at Sekigahara. Ishida arranged his troops in a formidable defensive position, flanked by two streams and occupying the high ground on the opposite banks.
Surprising Encounter Amid Fog
On October 21, 1600, the Tokugawa advance unit encountered Ishida’s army amid thick fog caused by earlier rainfall. Both sides were surprised and withdrew, but they remained aware of each other’s presence. Ishida maintained his defensive position while Ieyasu positioned his forces south of Ishida’s location. He directed his allies’ forces to the front lines and held his troops in reserve. As the wind cleared the fog, last-minute orders were issued, and the battle began.
Fukushima Masanori, who led the Tokugawa advance unit, launched a northward assault from the left flank of the Eastern Army along the Fuji River, targeting the right center of the Western Army commanded by Ukita Hideie. To support Fukushima’s attack, Ieyasu ordered simultaneous assaults from his right and center against the left flank of the Western Army. However, Shimazu Yoshihiro declined to follow these orders, as the daimyō of that era typically adhered only to respected commanders. Fukushima’s advance made gradual progress but exposed his flank to a counterattack from Ōtani Yoshitsugu on the opposite bank of the Fuji River.
Kobayakawa Hideaki, a daimyō courted by Tokugawa, initially remained neutral in the ongoing battle. Some theories suggest that Ieyasu eventually ordered his arquebuses to fire at Kobayakawa’s position to force him to take sides. However, the considerable distance between the positions of the Eastern Army and Kobayakawa’s forces makes this scenario improbable. Kobayakawa eventually entered the battle around noon, launching an attack on Ōtani’s position with dry gunpowder, resulting in a mostly ineffective charge. By the time Kobayakawa initiated this attack, Ōtani’s troops were already engaged in combat against the forces led by Tōdō Takatora and Oda Yūraku. It led to an outnumbered situation for Ōtani. As a result, several Western Army daimyos, including Wakisaka Yasuharu, Ogawa Suketada, Akaza Naoyasu, and Kutsuki Mototsuna, changed their allegiance, ultimately shifting the tide of the battle.
Ōtani’s Tactical Withdrawal
Ōtani, facing superior numbers, found himself compelled to withdraw, thereby exposing the vulnerable right flank of the Western Army. Fukushima and Kobayakawa then executed a maneuver to encircle this exposed flank, resulting in the severe weakening of Ishida’s right-wing forces and the pushing back of his central forces. Positioned atop Mount Nangu, Ishida’s remaining troops were under the command of Kikkawa Hiroie, who played a pivotal role as the frontline leader of the Mōri army. The overall command of the Mōri forces rested with his cousin, Mōri Hidemoto.
However, Hiroie refused to heed Hidemoto’s orders to launch an attack, effectively preventing the Chōsokabe army from initiating an assault. With the arrival of Ishida at the scene, Kikkawa Hiroie betrayed him, effectively holding the Mōri army in check. This betrayal ultimately resulted in Ishida’s defeat, leading to the dissolution of the Western Army, with its commanders scattering and fleeing. While some commanders managed to escape, others, such as Shima Sakon, chose to take their own lives. Ishida, Yukinaga, and Ekei were captured, whereas Shimazu Yoshihiro could return to their respective home provinces. Meanwhile, Mōri Terumoto and his forces remained entrenched within Osaka Castle, eventually surrendering to the Tokugawa forces. Subsequently, Ishida met his fate through execution.
Delays in Arrival at Sekigahara
Both factions involved in the conflict faced delays in reaching Sekigahara on schedule due to their involvement in other battles. Hidetada led a separate group using Nakasendō, but his forces failed to capture Ueda Castle, commanded by Sanada Masayuki. Despite the Tokugawa forces having a significant numerical advantage over Sanada’s 2,000 troops, they could not overcome the castle’s formidable defenses. Concurrently, a contingent of 15,000 Toyotomi troops encountered a delay caused by 500 troops under the command of Hosokawa Yūsai at Tanabe Castle. Some units deliberately slowed their march, resulting in many troops from both sides failing to arrive at the battlefield punctually.
The Toyotomi clan saw a notable decline in influence and reputation following the executions of Ishida Mitsunari, Konishi Yukinaga, and Ankokuji Ekei on November 6. Tokugawa Ieyasu proceeded to reorganize land and fiefs, rewarding those who had supported him and imposing penalties on those who had opposed him. It resulted in Ieyasu gaining control of many former Toyotomi territories. Initially perceived as an internal conflict among Toyotomi vassals, the battle’s significance grew after Ieyasu assumed the position of shōgun in 1603.
In 1664, Hayashi Gahō, a historian from the Tokugawa era, summarized the aftermath of the battle, praising the establishment of peace and acknowledging Ieyasu’s martial prowess. He expressed the hope that this splendid era would endure for countless generations.
Clan Resentment and Collaboration
During the Sekigahara battle, numerous clans, especially those aligned with the Western side, nursed grievances due to their displacement or perceived defeat. Three clans, led by Mōri Terumoto, resented their relocation to Chōshū Domain despite their non-participation in the battle. Shimazu, under the leadership of Shimazu Yoshihiro, attributed their defeat to inadequate intelligence-gathering and asserted their independence from the Tokugawa shōgunate. Meanwhile, the Chōsokabe clan, led by Chōsokabe Morichika, suffered the loss of their title and Tosa domain, followed by exile. The Yamauchi clan, led by Chōsokabe Morichika, established a distinction between their retainers and former Chōsokabe retainers, subjecting the latter to lower status and discriminatory treatment. This class division persisted even after the clan’s downfall. Eventually, descendants of these three clans would collaborate to contribute to the downfall of the Tokugawa shogunate, paving the way for the Meiji Restoration.
Before the clash at Sekigahara, Ishida Mitsunari seized control of Osaka Castle and formulated a plan to secure hostages from relatives loyal to the Toyotomi clan. He aimed to coerce rival generals into supporting his cause, utilizing noblewomen Hosokawa Gracia, Yamauchi Chiyo, and Kushihashi Teru as political leverage. Tragically, Hosokawa Gracia met her end at the hands of a family soldier named Ogasawara Shōsai, who sought to preserve her honor. The remaining castle inhabitants chose seppuku (ritual suicide) to avoid capture. This incident significantly damaged Ishida’s reputation and hindered his ability to recruit additional allies, including some who secretly practiced Christianity.
Following the passing of Hideyoshi, Kodain-in departed from Osaka Castle and assumed the role of a castellan in Kyoto. Yodo-dono, Hideyoshi’s second wife, inherited the political authority of both Hideyoshi and Kodain-in. While she played a part in the organization of the Western army, her involvement in the campaign itself was not substantial. After Ieyasu triumphed over Mitsunari at Sekigahara, Kodain-in provided refuge to several women from the Western army at her residence.
Kuki Yoshitaka, a distinguished general who had served both Nobunaga and Hideyoshi, fought alongside the Western forces, while his son, Kuki Moritaka, aligned with the Eastern forces under Tokugawa Ieyasu. Yoshitaka chose seppuku before receiving news of Moritaka’s decision. Legend has it that the rōnin Miyamoto Musashi was present at the battle within Ukita Hideie’s army and managed to escape unscathed from the defeat suffered by Hideie’s forces. However, no concrete evidence exists to confirm or refute his presence or absence.
Tokugawa’s forces employed cannons from the Liefde, the trading ship on which English sailor William Adams arrived in Japan. Still, it is improbable that Adams himself participated in the battle.
The Legacy of the Battle of Sekigahara
Following the Battle of Sekigahara, Tokugawa Ieyasu emerged victorious, consolidating his authority over Japan by establishing the Tokugawa Shogunate. This reign lasted more than 250 years until the Meiji Restoration in 1868. One of his initial actions involved redistributing land to his loyalists while penalizing those who had supported his adversaries. He also introduced a system of alternate attendance, known as sankin-kotai, compelling regional lords to spend alternating years in Edo, the new capital, to maintain control. Tokugawa’s era was marked by a prolonged period of tranquility and stability, referred to as the Pax Tokugawa, during which he endeavored to centralize the government and unite Japan.
Additionally, he implemented the sakoku policy, translating to the “closed country,” which limited foreign contact to preserve Japanese culture and traditions. Nevertheless, Tokugawa encountered challenges during his rule, including uprisings by dissenting groups and the arrival of foreign powers, such as the United States, which aimed to open Japan to trade. Ultimately, these difficulties contributed to the decline of the Tokugawa Shogunate in the mid-19th century, paving the way for the Meiji Restoration and a new era in Japanese history.
The Battle of Sekigahara emerged as a pivotal conflict, effectively concluding the Warring States period. Following the battle, Mitsunari attempted to flee but was captured and defiantly executed in Kyoto. Ieyasu further solidified his position, assuming the title of shogun in 1603, ushering in a Tokugawa dynasty that endured for 260 years. The influence of Hideyoshi’s family persisted as a source of contention for Ieyasu until their ultimate elimination in 1615 during the Siege of Osaka Castle.
Beyond its historical impact, the battle left an enduring imprint on Japanese culture, contributing phrases like “tenkawakeme,” signifying a decisive, fateful moment, and inspiring portrayals of its combatants in literature, film, anime, and even video games. Most notably, Sekigahara symbolizes the division between eastern and western Japan, marked by many cultural distinctions, including variations in soup stock recipes and customs like the preferred side for standing on escalators.
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