Battle of Sekigahara

The Battle of Sekigahara is one of the most famous battles throughout all of history.
A decisive battle that Tokugawa Ieyasu won and eventually led the way to him being the Shogunate.

On October 21, 1600 the combined armies of Tokugawa Ieyasu fought with Toyotomi Hideyori and his combined forces at the battle of Sekigahara.

The battle was fought around a small village called Sekigahara that sat astride a crossroads under the heights of Mt.'s Sasao, Matsuo, and Nangu. In retrospect a strategically important point, the choice of the field of battle had been inadvertant. Ishida Mitsunari had hoped to meet Ieyasu somewhere further east; Ieyasu's primary objective had been Sawayama castle. Although Ieyasu's march was done quite hastily Ishida Mitsunari more than welcomed the fight, since he had the slight terrain advantage.

Map of army positions

Western army troops occupied the heights around Mt. Nangu and Matsuo, with Ishida himself positioned somewhat northwest of Sekigahara and flanked by Mt. Sasao. Ieyasu's men were deployed along the Nakasendo, with the vanguard facing Mitsunari, and were exposed to an attack in the flanks, especially by the western troops on Mt. Matsuo. Luckily for Ieyasu, those men were under the command of Kobayakawa Hideaki, who had already decided to betray his western compatriots.

The fighting began in a rainy dawn. The forward Tokugawa units attacked and became heavily engaged with contingents under Ukita Hideie, Otani Yoshitsugu, and Konishi Yukinaga. No real advantage was being gained until the defection of Kobayakawa Hideaki happened around noon. Hideaki, who commanded one of the strongest Western contingents present, turned the tide in Ieyasu’s favor. Meanwhile, the 25,000 or so western troops arrayed on the slopes of Mt. Nangu under the Mori and Chosokabe were largely idle. Kikkawa Tsunie, commanding the vanguard, had himself decided not to fight Ieyasu, and his immobility forced those to his rear to do the same. Finally, the western forces began to break and a general rout ensued.

By the end of the day's killing, Ishida Mistunari’s forces had scattered and as many as 60,000 heads would be taken. Tokugawa’s victory was owed in large part to Kobayakawa’s defection and the inactivity of the Mori contingents present. Ishida and Konishi Yukinaga were later captured and executed.


So victory went to the eastern coalition. Ieyasu used the victory at Sekigahara to assert his national authority over the military estate and to make drastic changes in the composition and placement of the daimyo and their holdings throughout Japan. In the immediate aftermath of the battle, eighty-seven daimyo who had opposed Ieyasu were defeated and their lands confiscated. The lands of three others were drastically reduced in size. All together, a total of 6,221,690 koku were taken from Ieyasu's daimyo opponents. Another 1.35 million koku were taken from the Toyotomi house and made available for reallocation to other daimyo or for inclusion in Ieyasu's personal holdings. Even greater changes were brought about by the transfer of forty-three daimyo from one location to another and the creation of new daimyo. The authority to invest new daimyo rested on Ieyasu's claim to hegemony over the warrior estate. Prior to the battle Ieyasu counted among his cadet branch heads and hereditary housemen forty whose holdings were of 10,000 koku or more. He was now able to set these men out as full-fledged daimyo under his own patent. All were given domain increases. Another twenty members of his houseband who, as of 1600, held fiefs of less than 10,000 koku were raised to daimyo status. Finally, he granted daimyo status to eight rear vassals who had distinguished themselves in Ieyasu's eyes.


Table showing army sizes

Table is sortable

Eastern Army Size Western Army Size
Tokugawa Ieyasu 30000 Mori Terumoto Not present
Honda Tadakatsu 500 Ishida Mitsunari 4000
Hosogawa Tadoaki 5000 Shima Sakon 1000
Ii Naomasa 3600 Gamon Bitchu 1000
Matsudaira Tadayoshi 3000 Akaza Naoyasu 600
Tsutsui Sadatsugu 2850 Chosokabe Morichika 6600
Arima Toyouji 900 Kikkawa Hiroie 3000
Asano Yokunaga 6510 Mori Hidemoto 15000
Fukushima Masanori 6000 Ankokuji Ekei 1800
Ikeda Terumasa 4560 Kobayakawa Hideaki 15600
Ikoma Kazumasa 1830 Konishi Yukinaga 4000
Kanamori Nagachika 1140 Kuchiki Motosuna 600
Kato Yoshiaki 3000 Natsuka Masaie 1500
Kuroda Nagamasa 5400 Ogawa Tsuketada 2100
Kyogoku Takatomo 3000 Otani Yoshitsugu 600
Oda Yuraku 450 Otani & Kinoshita 3500
Tanaka Yoshimasa 3000 Shimazu Yoshihiro 1500
Terazawa Hirotaka 2400 Toda & Hiratsuka 1500
Todo Takatora 2490 Toyotomi Retainers 2000
Yoshida Shigekatsu 1200 Ukita Hideie 17000
Wakizaka Yasuharo 990
Total: 88,888 Total: 81,890

Source: Bryant, 1995:25.




Here is a documentary made by the BBC on Tokugawa Ieyasu at the Battle of Sekigahara.



Sekigahara today (Japanese website)
The Battle of Sekigahara Wikipedia
Sekigahara Board Game