Ishida Mitsunari and Tokugawa Ieyasu were in an ideological struggle.
Ieyasu wanted dominion in Japan, while Mitsunari was a loyalist to Toyotomi and wanted to see this lineage in power for years to come.
Even though Ieyasu was one of the five regents that Hideyoshi Toyotomi appointed [regents called tairo] to ensure the safety of Toyotomi’s son and to help lead on behalf of the Toyotomi lineage until the son comes of age, Ieyasu wanted rule over Japan.
When Hideyoshi died, Ieyasu moved to Hideyoshi’s Fushimi castle in Kyoto.
And he built alliances through marriages with his clan and the neighboring ones to secure his power.
Although Mitsunari was not among the five regents that Hideyoshi had appointed before Hideyoshi’s death, Mitsunari was Toyotomi’s loyalist. Hence, he created an alliance with the daimyos to assert the Toyotomi’s rule.
Mitsunari ordered the death of Ieyasu, but it failed, and Ieyasu spared his life, following Ieyasu’s move to Osaka Castle to become the protector of Hideyori [Hideyoshi Toyotomi’s son] to extend his power.
In October 1600, The Western Army (Ishida Mitsunari) fought with Tokugawa’s Eastern army. But four Western army troops had defected to Ieyasu, leading to the Western army retreating.
Eventually, Tokugawa’s army succeeded, which paved the way to create a Tokugawa shogunate. Japan was then unified underneath this reign.
Dominion: power or rule over
Ideological: idea or belief system
Regent: in the absence of an actual ruler a person takes the role of looking after the state or province
Shogunate: a militarised regime in Japan first created by Minamoto Yoritomo called the Kamakura Shogunate, Tokugawa Ieyasu created the last shogunate known as the Tokugawa Shogunate
Hudson, M. (2021, October 14). Battle of Sekigahara. Encyclopedia Britannica. https://www.britannica.com/event/Battle-of-Sekigahara
Snow, P. (2021). BATTLES MAP BY MAP. FOREWORD BY PETER SNOW. Dorling Kindersley