|Battle of Sekigahara|
|Date||October 21, 1600|
|Location||Sekigahara, Gifu province|
|Result||Tokugawa victory; beginning of Tokugawa shogunate|
|Toyotomi army||Tokugawa army|
|Mitsunari Ishida||Ieyasu Tokugawa|
|Sakon Shima |
Terumoto Mouri (difected)
Hideaki Kobayakawa (defected)
| Tadakatsu Honda |
The Battle of Sekigahara was a decisive battle on October 21, 1600 which cleared the path to the Shogunate for Ieyasu Tokugawa. Though it would take three more years for Ieyasu to consolidate his position of power over the Toyotomi clan and the daimyo, Sekigahara is widely considered to be the unofficial beginning of the Tokugawa shoganate, which was the last shoganate to control Japan.
Before the BattleEdit
Ieyasu Tokugawa was no longer rivaled in terms of seniority, rank, reputation and overall influence within the Toyotomi clan after the death Toshiie Maeda. Rumors started to spread stating that Ieyasu, at that point the only surviving ally of Nobunaga Oda, would take over Hideyoshi's legacy just as Nobunaga's was taken. This was especially evident amongst the loyalist bureaucrats, who suspected Ieyasu of agitating unrest amongst Toyotomi's former vassals.
Later, a supposed conspiracy to assassinate Ieyasu surfaced, and many Toyotomi loyalists, including Toshiie's son, Toshinaga Maeda, were accused of taking part and forced to submit to Ieyasu's authority. However, Kagekatsu Uesugi, one of Hideyoshi's appointed regents, defied Ieyasu by building up his military. When Ieyasu officially condemned him and demanded that he come to Kyoto to explain himself before the emperor, Kagekatsu's chief advisor, Kanetsugu Naoe responded with a counter-condemnation that mocked Ieyasu's abuses and violations of Hideyoshi's rules, in such a way that Ieyasu was infuriated.
Afterwards, Ieyasu summoned the help of various supporters and led them northward to attack the Uesugi clan, which at that moment were besieging Hasedo, but Mitsunari Ishida, grasping the opportunity, rose up in response and created an alliance to challenge Ieyasu's supporters, also seizing various daimyo as hostages in Osaka Castle.
Ieyasu then left some forces led by Masamune Date to keep the Uesugi in check and marched west to confront the western forces. A few daimyo, most notably Masayuki Sanada, left Ieyasu's alliance, although most, either bearing grudges against Mitsunari or being loyal to Ieyasu, stayed with him.
- Musashi Miyamoto also fought at Sekegahara with the western army.