Nirayama Castle (韮山城 Nirayama-jō) is located in the northern neck of Izu Peninsula, in present-day Izunokuni. In 1493, Hōjō Sōun who had risen to power in Kokokuji Castle defeated Horikoshi-kubō Ashikaga Chachamaru who had ruled Izu and put the entire peninsula under his control. He rebuilt Nirayama Castle and moved there from Kokokuji Castle, setting it up as his new headquarters. Later, Soun captured Odawara Castle and extended his rule over the provinces of Sagami and Musashi. However, he maintained Nirayama Castle as his power base until his death. When Sōun's son Ujitsuna...

Nagahama Castle (長浜城 Nagahama-jō) is located on the southern edge of Numazu City in Izu Peninsula (Shizuoka Prefecture). The hilltop castle was a naval base built in 1579 by the Late Hōjō. After the invasion of Suruga (modern-day Shizuoka) in 1569, the Takeda finally had access to the sea and immediately started to build up naval forces they could deploy against the Hōjō in the east and the forces of Tokugawa Ieyasu in the west. The Hōjō constructed Nagahama Castle to confront the Takeda navy. The site was ideal, as it was located in a secluded bay with deep water that also allowed larger...

Kokokuji Castle (興国寺城 Kōkokuji-jō, also known as 根古屋城 Negoya-jō) is located in Numazu in Shizuoka Prefecture. It was constructed sometime between 1469 and 1487 and given to Hōjō Soun (or Ise Shinkuro at that time) for services rendered to the Imagawa clan. The rise of the Late Hōjō in the Kantō region began right here. However, the Hōjō did not rule the castle continuously; when Soun invaded the Izu Peninsula in 1491 it was handed over to Imagawa Yoshimoto who later renovated the castle. In the following decades, the castle changed hands several times between the Imagawa, the Hōjō and the...

Mount Omuro (大室山 Ōmuroyama) is a volcano south of Ito City on the eastern coast of the Izu Peninsula. Extinct for 3,700 years, the cone-shaped mountain is completely covered in grass and has a circular trail around its crater mound at an altitude of 580 meters. The trail is about one kilometre in length. The Ōmuroyama Volcano Geosite is part of the Fuji-Hakone-Izu National Park (富士箱根伊豆国立公園 Fuji-Hakone-Izu Kokuritsu Kōen) that spans Yamanashi, Shizuoka, Kanagawa and parts of Tokyo. The summit of Mount Ōmuro can only be accessed by chairlift (about 5 minutes) and offers spectacular...

Kakegawa Castle (掛川城 Kakegawa-jō) is a hilltop (hirayama-type) castle located in Kakegawa City in western Shizuoka Prefecture. Listed in the Top 100 Castles of Japan, it is considered to be one of the finest examples of reconstructed Japanese castles. Kakegawa Castle in August 2015 History The castle was originally built in 1497 by Asahina Yasuhiro, a retainer of the Imagawa clan which ruled over Suruga Province, the central part of modern-day Shizuoka Prefecture. After Imagawa Yoshimoto (今川 義元, 1519-1560) was killed in the Battle of Okehazama in June 1560, his territories were divided...