Toyotomi Hideyoshi reportedly hid the castle's construction from the Hojo clan by keeping the mountain slope covered in trees until the final day.
The castle served as the primary command center for the 1590 military campaign against the Odawara Hojo.
It is officially designated as a National Historic Site of Japan.
Construction involved the recruitment of master stone masons from Anou, who utilized advanced masonry techniques for the era.
The name 'Ichiya' (one night) refers to the psychological warfare tactic used to overwhelm the enemy's morale.
The site remains largely an earthen fortress with limited vertical stone masonry compared to conventional Japanese castles.
It is a popular spot for cherry blossom viewing during the spring season.
Ishigakiyama Castle, also known as Ishigakiyama Ichiya Castle, is a historical site constructed by Toyotomi Hideyoshi in 1590 during the Siege of Odawara. It is defined by its 'one-night castle' legend, where trees were cleared to make it appear as though the fortress was built overnight to demoralize the Hojo clan. The site features original stone wall ruins preserved within the Ishigakiyama Castle Historical Park. Visitors can access panoramic views overlooking Sagami Bay and the city of Odawara. The park is characterized by its lush greenery and remnants of dry moats and earthen ramparts. It remains an open-air historical site maintained by the City of Odawara. The area is situated on the summit of Mount Ishigaki at an elevation of approximately 262 meters.
The stone rampart area near the main enclosure, which offers the widest panoramic view of the bay.
Bring comfortable walking shoes suitable for gravel and uneven historical terrain.
Carry drinking water, as there are limited facilities on the mountain summit.
Visit on a clear day to ensure visibility of the ocean and nearby mountain ranges.
Do not expect to see a reconstructed wooden castle tower; the site consists strictly of ruins and historical topography.
Maintain the integrity of the stone walls by not climbing on them; remain on marked pathways to preserve the historic landscape.
