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.
At the Battle of Sekigahara on October 20, 1600, Tadaoki commanded a contingent of 5,000 men within the Tokugawa army and faced off against Shima Sakon's troops.