Mōri Terumoto
The rulers of Chōshū were the descendants of the great Sengoku warlord Mōri Motonari. Motonari was able to extend his power over all of the Chūgoku region of Japan and occupied a territory worth 1,200,000 koku. After he died, his grandson and heir Mōri Terumoto became "daimyō" and implemented a strategy of alliance with Toyotomi Hideyoshi. This would later prove to be a great mistake. After Hideyoshi's death, the "daimyō" Tokugawa Ieyasu challenged the Toyotomi power and battled with Hideyoshi's trusted advisor Ishida Mitsunari at the Battle of Sekigahara. Mōri Terumoto was the most powerful ally of the Toyotomi and was elected by a council of Toyotomi loyalists to be the titulary head of the Toyotomi force. However the Toyotomi forces lost the battle due to several factors tied to Mōri Terumoto: