大坂の陣
In 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. Afterwards, He was awarded a fief in Buzen (Kokura, 370,000 koku) and went on to serve at the Siege of Osaka (1614–1615).