The Battle of Sekigahara

18th century screen depicting the Battle of Sekigahara

Setting the scene

Between 1585 and 1590, Toyotomi Hideyoshi, Lord of Osaka completed the unification of Japan started by Oda Nobunaga. Upon his death in 1598, a regency council was implemented to govern in the name of his 10 year old son Hideyori. The regency council comprised the five most powerful Lords of the land, including Ishida Mitsunari and Tokugawa Ieyasu.

Quickly two factions began to emerge: The loyalists led by Ishida Mitsunari proclaimed they were protecting Hideyori’s interests and fighting against Tokugawa Ieyasu’s personal ambition.

Ishida Mitsunari (1559-1600), Lord of Hikone, a medium-sized clan on the banks of Lake Biwa with Sawayama Castle as main fortress, was known as a politician, not a military strategist. As a loyalist and protector of Hideyori, he had the loyalty of many clans, most of them West of Kyoto. His army known as “Army of the West” was 80,000 men strong. Of the 214 lords who had a domain with revenues superior of 10,000 rice koku, 87 were allied to the Army of the West (80 were either killed in the battle, executed, exiled or imprisoned).

Tokugawa Ieyasu (1543-1616) was the richest and most powerful Lord, known for his military prowess and cunning. He controlled the East of Japan and his army “Army of the East” was 74,000 strong.

The Battle of Sekigahara

In July 1600, the Regency Council led by Ishida was in session in Fujimi Castle near Osaka when Tokugawa Ieyasu learned that the Uesugi Clan, an Ishida’s allied had attacked his holdings in the North. Ieyasu left Osaka area with its troops to defend its territories. Uesugi conquered swiftly several castle towns, forcing Ieyasu to move quickly against him. These attacks were in fact only a diversion as Ishida wanted to take Tokugawa between two prongs. But Ieyasu, well informed by his spy ring, sent only his son Hidetada with half his troops towards the north while he attacked and conquered Gifu castle (See Kano station #53). Ishida and his army were just behind Ieyasu, but decided to move into the well-defended Ogaki Castle (see Akasaka station #56). Ieyasu prepared then to move against Sawayama, Ishida’s main castle near Hikone (see Banba station #62), hoping to draw Ishida out of Ogaki Castle. And this worked: Ishida decided to go and block the Sekigahara gap.

The Army of the West moved under heavy rain towards Mt.Sasao on the foothills of Mt.Ibuki. The Army of the East moved in Sekigahara village on the Nakasendo road where Ieyasu waited for his son Hidetada and his 30,000 men. But Hidetada was laying siege to another castle and did not reach Sekigahara on time, much to his father’s fury.

On October 21st 1600 at 8.00am, in a heavy fog, the first Tokugawa men came into contact with Ishida troops. They retreated rapidly and by 9.00am when the fog lifted, two huge armies were facing each others with over 150,000 men on the battlefield. The Ishida battalions were placed in a crescent-shaped position, occupying the foothills while Tokugawa troops were massed in the plain.

The strength of Tokugawa’s army was its arquebus battalions. Arquebus, the first firearms imported 60 years before by the Portuguese, were very expensive and Ieyasu’s wealth allowed him to equip several regiments. Ieyasu’s army started with several volleys which weakened Ishida’s frontline. This was followed by an assault to the centre by the Red Devils, Ii Naomasa ‘s elite troops clad in their red armour. But entrenched behind wooden palisades, Ishida’s troops resisted and General otani launched a counter-attack to the South, trying to catch them in a pincer movement.

A furious hand-to-hand combat followed in the center where Tokugawa’s captains were fighting against Ishida’s. In close combat, arquebus were useless and Tokugawa’s army, missing his son’s troops started to move back. The Army of the West rallied to launch a major assault.

Around 1.00pm, Ishida ordered the Mori Clan, in position on Mt.Minamimiya to send his cavalry and the Kobayakawa Clan to move forward and support General Otani. But Mori did not move and Kobayakawa changed sides and attacked Otani. At the same time, Ieyasu launched his reserve troops.

The Army of the West started to falter, then collapsed. The last units were killed trying to protect Ishida’s fleeing from the battlefield. No surrender was accepted and officers were beheaded with pyramids of heads all over the field. Ishida and his allies were caught a few days later and executed.

Consequences

This victory ensured Tokugawa Ieyasu's domination over Japan. In 1603, the emperor awarded him the title of Shogun and for the first time for over a century, a real executive power was governing. The Tokugawa remained in power until 1868 when the Meiji emperor reclaimed the power.

After a last campaign to eliminate Hideyori, Toyotomi Hideyoshi’s heir in Osaka in 1614-1615, Ieyasu transferred the power to his son Hidetada and retired to a temple. He died in 1616 and is buried in Nikko, north of Tokyo.

This period, known as Edo period gave 250 years of stability to Japan. The Tokugawa Shoguns strengthened their grip on power by implementing the Sankin-kotai or alternate residence. The daimyo had to move periodically between Edo and his clan, typically spending alternate years in each place. His wife and heir were required to remain in Edo as hostages. The expenditures necessary to maintain lavish residences in both places, and for the procession to and from Edo, placed financial strains on the daimyo making them unable to wage war. And to facilitate the daimyos’ frequent travels, the shogunate encouraged the building of roads, such as Nakasendo and the construction of the stations.

Tokugawa Ieyasu

Ieyasu's command post next to Nakasendo Road

The battlefield seen from Ieyasu's command post

Ishida Mitsunari

Ishida's command post on the hill

The battlefield seen from Ishida's command post

The battlefield

The defensive fences of the Army of the West

The execution ground