The Battle of Sekigahara was a decisive battle on October 21, 1600 (Keichō 5, 15th day of the 9th month) in what is now Gifu Prefecture, Japan, at the end of the Sengoku period. This battle was fought by the forces of Tokugawa Ieyasu against a coalition of Toyotomi loyalist clans under Ishida Mitsunari, several of which defected before or during the battle, leading to a Tokugawa victory. Wikipedia