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 some time 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 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 Takeda. The Takeda took control of it in 1571, but lost it to Tokugawa Ieyasu in 1582 when Takeda Katsuyori and his clan were ultimately destroyed. In 1590, Ieyasu had to move to Kantō and one of Toyotomi Hideyshi's followers, Nakamura Kazūji (中村 一氏, d. 1600), took residence at Kokōkuji Castle.
After the Battle of Sekigahara, Amano Yasukage (天野 康景, 1537-1613), also known as the “impartial Saburobe”, served at the castle. One day, one of Yasukage's samurai killed vassals who were going to steal timber. The shogunate asked Yasukage to hand over his retainers, as the thieves were farmers of the adjacent shogunal demesne. Yasukage however, convinced that his retainers had acted rightfully, resisted the shogunal order and had to leave the castle in 1607. After that, the domain and Kokōkuji Castle were abandoned. Yasukage died in 1613 at Sainenji Temple in Minamiashigara close to Odawara.
We rented a car at Mishima Station and visited Kokōkuji, Nagahama and Nirayama, all castles of the Hōjō clan. I turned to Kokōkuji Castle at the north side of Negoya crossing, along Prefectural Route 22, and parked in front of Homi Shrine.
There, from the third enclosure, we had a great view of the main and second enclosure. The structure of the castle was of renkaku-shiki style (連郭式), where honmaru and ninomaru are arranged side by side, causing the depth of the castle to increase, but the sides and rear of the honmaru are exposed, making the castle more vulnerable to attacks on areas other than the central gate. The main enclosure was built on an elevated plateau.
Stone walls and foundation stones of a yagura, a castle tower.
The considerably deep dried moat was located on the northern side of the main enclosure. Although the size of the castle was small, with marshes in the east and west it seems to have been quite a stronghold.
The main enclosure seen from the north.
The Shinkansen runs along the north side of the castle.
Suruga Bay and Izu Peninsula seen from the main enclosure. What would have been Hōjō Soun's thoughts on this vista?
There are plans to maintain the former castle grounds as a historical park. I suppose that these days there are many places where castles from the Sengoku Period are frantically restored.
Date of visit: 30th June 2013
- Address: Negoya, Numazu-shi, Shizuoka - Map
- Transportation: 30 minutes from JR Tokaido line Hara station on foot
10km from Tomei Expwy Numazu IC via Prefectural Route 22
- 興国寺城 基本情報 - 静岡県の城総覧 | Shizuoka城と戦国浪漫 (in Japanese)