Yamanaka Castle was a Later Hojo fortress that could not have existed without the foundation of Izu and Sagami control established by Hojo Soun. Soun's seizure of Izu launched the Later Hojo's dominance of the Kanto, and Yamanaka Castle became the westernmost key point in their defensive network.

In the third month of 1590, as the opening battle of his Odawara Campaign, Toyotomi Hideyoshi sent some 70,000 troops — vanguarded by his nephew Hidetsugu — against Yamanaka Castle, the gateway on the Tokaido. The roughly 4,000 Hojo defenders under Matsuda Yasunaga relied on the formidable shoji-bori moats, but the castle fell in just half a day before overwhelming numbers. The shock of this assault propelled Hideyoshi's drive to encircle Odawara and force its bloodless surrender.