He later defeated Toyotomi Hideyori , son of Hideyoshi , at the Siege of Osaka in 1615 , and emerged as the political leader of Japan .
Tokugawa Ieyasu made Edo Castle his base after he was offered eight eastern provinces by Toyotomi Hideyoshi .
Tokugawa Ieyasu later defeated Toyotomi Hideyori , son of Toyotomi Hideyoshi , at the Siege of Osaka in 1615 , and emerged as the political leader of Japan .
Tokugawa Ieyasu made Edo Castle his base after he was offered eight eastern provinces by Toyotomi Hideyoshi .