On October 20, 1600 at the Battle of Sekigahara, Tadaoki commanded 5,000 men in the Tokugawa vanguard and clashed with the forces of Shima Sakon.
On October 20, 1600 at the Battle of Sekigahara, Tadaoki led an army unit of 5,000 soldiers in the Tokugawa forces and encountered Shima Sakon's group.