Battle of Sekigahara - The Battle

The Battle

Mitsunari, in his home Sawayama Castle, met with Ōtani Yoshitsugu, Mashita Nagamori, and Ankokuji Ekei. Here, they forged the alliance, and invited Mōri Terumoto, who actually did not take part in the battle, to be its head.

Mitsunari then officially declared war on Ieyasu and lay siege to the Fushimi Castle, garrisoned by Tokugawa retainer Torii Mototada on July 19. Afterwards, the western forces captured various Tokugawa outposts in the Kansai region and within a month, the western forces had moved into the Mino Province, where Sekigahara was located.

Back in Edo, Ieyasu received news of the situation in Kansai and decided to deploy his forces. He had some former Toyotomi daimyo engage with the western forces while he split his troops and marched west on the Tōkaidō towards Osaka Castle.

Ieyasu's son Hidetada led another group through Nakasendō. However, Hidetada's forces were bogged down as he attempted to besiege Sanada Masayuki's Ueda Castle. Even though the Tokugawa forces numbered some 38,000, an overwhelming advantage over the Sanada's mere 2,000, they were still unable to capture the strategist's well-defended position. At the same time, 15,000 Toyotomi troops were being held up by 500 troops under Hosokawa Fujitaka at Tanabe Castle in Wakayama Prefecture. Some among the 15,000 troops respected Hosokawa so much they intentionally slowed their pace down. Both these incidents resulted in a large number of Tokugawa and Toyotomi troops not to show up in time at the battlefield of Sekigahara.

Knowing that Ieyasu was heading toward Osaka, Mitsunari decided to abandon his positions and marched to Sekigahara. On September 15, 1600 (Keichō 5, 8th day of the 8th month), the two sides started to deploy their forces. Ieyasu's eastern army had 88,888 men, whilst Mitsunari's western army numbered 81,890. There were about 20,000 arquebusers and other forms of hand-held gunners deployed in the battlefield, corresponding to over 10% of all troops present.