Odawara Castle was the seat of the Hojo Five Generations for a century. At its peak it was Japan’s largest fortified city, with a 9-km defensive perimeter called Sogamae that turned the entire town into a fortress. The castle withstood attacks by Uesugi Kenshin (1561) and Takeda Shingen (1569) but fell to Toyotomi Hideyoshi’s 220,000-strong army after a three-month siege in 1590, ending the Hojo era. Under the Tokugawa, it served the Okubo clan as the seat of Odawara Domain and the ninth post-station of the Tokaido. Today, the 1960 reconstructed keep and the still-visible Sogamae earthworks preserve this layered history.