Nirayama Castle

Izunokuni, Japan, Japan

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Nirayama Castle is a hilltop Japanese castle ruin in the Nirayama neighborhood of Izunokuni City, at the base of the Izu Peninsula in Shizuoka Prefecture, famous for its role in the rise of the Hōjō clan and its later connection to the 1590 Siege of Odawara.

Originally held by various local lords in the late Muromachi period, the castle was drastically expanded and used as a regional base by Ise Shinkuro, better known as Hōjō Sōun, after he captured the area in 1493; he moved his main residence here from Kokokuji Castle while consolidating control over Izu and pushing into Sagami, and though his son later shifted the clan’s main seat to Odawara Castle, Nirayama remained a key stronghold for the Hōjō in Izu.

During Toyotomi Hideyoshi’s Odawara campaign in 1590, Hōjō Ujinori held Nirayama Castle with several thousand men and successfully resisted a much larger force for three months before surrendering, and after the Hōjō defeat the castle was abandoned, leaving only terraced earthworks, moats, and stone reinforcement walls on the long, narrow hill.

Today the site is a National Historic Site (designated in 2025) with walking trails that follow the castle’s layout, but no buildings survive, and the area is complemented by nearby historical spots such as the Egawa family residence and the Nirayama reverberatory furnace, making it a compact but historically rich destination about a 10–15 minute walk from JR Nirayama Station.