After Hideyoshi's death and in accordance with his will, Hideyori TOYOTOMI moved to Osaka-jo Castle; after which Ieyasu TOKUGAWA, leader of the council of 5 elders, moved into this castle and took over government.
秀吉の死後、その遺言によって豊臣秀頼は大阪城に移り、五大老筆頭の徳川家康が代わってこの城に入り政務をとった。