Hojo Soun took control of Odawara Castle in 1495, and set in motion five generations of Hojoregional rule. In preparation for the 1590 invasion by Toyotomi Hideyoshi, a huge 9km-long outer earthen wall and moat, known as a sogamae, was completed. However, because of the overwhelming Toyotomi military force, there was no choice for the Hojo but to open the castle in a bloodless surrender. After the damage of a 1633 earthquake, major renovation work was carried out, and the existing castle was completed. The main Hojo period ruins have been preserved as a nationally designated Historic Site, with some of the outer moat and earthen walls remaining. The tenshu was rebuilt in 1960. In 1997, the Akagane-mon Gate and Ni-nomaru inner moat were restored based on excavation results. The Umaya-kuruwa-mon Gate has been also restored, returning parts of Odawara to its former appearance.