Saku Castle
Sakujō is an okajiro (hilltop castle) ruin in Mikkabi Township of Hamana Ward, Hamamatsu Municipality. It is on a small peninsula jutting into Lake Inohana, an inlet of Lake Hamana. Ruins remain in the form of earthworks, including large dorui (earthen ramparts), deep karabori (dry moats), and baile
History
Sakujō was first built in 1348 by Hamana Kiyomasa. The castle is mentioned in the Munenaga Nikki as hosting a renga party in 1522, being referred to in that document as the 'Hamana (clan name) Bitchū-mori (court title) Yakata (manor hall)'. The Hamana Clan were vassals of the Imagawa Clan. Sakujō likely also played a more practical role in protecting shipping in the lake.
In 1560, following the battle of Okehazama and the death of Imagawa Yoshimoto, Matsudaira forces invaded Tôtōmi Province. Matsudaira general Honda Tadakatsu, taking up position to besiege Sakujō, advised castellan Ôya Masayori, who was defending, to surrender. Ôya Masayori was the chief vassal of the Hamana Clan. His lord, Hamana Yorihiro, was away fighting, and the lord's family had already fled to Kai. Chief Ôya decided it was prudent to surrender, retreating from Sakujō. Sakujō was captured and given to Honda Nobutoshi.
Incidentally, the castle's fortifications, which are not insignificant, may well have been built up to defend against the Matsudaira. In 1583, Honda Nobutoshi built and relocated to Nojijō to the north, and Sakujō was abandoned.
Field Notes
Sakujō is an okajiro (hilltop castle) ruin in Mikkabi Township of Hamana Ward, Hamamatsu Municipality. It is on a small peninsula jutting into Lake Inohana, an inlet of Lake Hamana. Ruins remain in the form of earthworks, including large dorui (earthen ramparts), deep karabori (dry moats), and baileys.
The fort is small but well constructed. There is a main bailey with a koguchi (tiger's maw gate) ruin, and an outer umadashi (barbican) connected to the honmaru (main bailey) by a dobashi (earthen bridge). There is what looks like an expanded creek facing inland between the honmaru and umadashi, and on the lake-facing side there is a complex of trenches and berms in an impressive array. These trenches slope down the hill, and so they are tatebori (climbing trenches), with dorui in between.
Because the entrance to the site, maintained as sort of park, also appears like a trench, and there is some flat terrain beyond, it is thought that the castle also had an outer bailey of some sort, but the structure of the fort is not clear in this section.
Note: This site is also sometimes called Mikkabi-Sakujō.
Gallery
| Castle Profile | |
|---|---|
| English Name | Saku Castle |
| Japanese Name | 佐久城 |
| Alternate Names | Mikkabi-Sakujō (三ヶ日佐久城) |
| Founder | 1348; c.1560 |
| Year Founded | Hamana Kiyomasa; Hamana Yorihiro |
| Castle Type | Mountaintop |
| Castle Condition | Ruins only |
| Historical Period | Pre Edo Period |
| Artifacts | Dorui, Dobashi, &c. |
| Features | trenches |
| Visitor Information | |
| Access | Tsuźuki Station on the Tenryū-Hamanako Line; 25 min walk. |
| Hours | 24/7 free; park |
| Time Required | 20 minutes |
| Location | Hamamatsu, Shizuoka Prefecture |
| Coordinates | 34.78714, 137.56636 |
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| Admin | |
| Added to Jcastle | 2025 |
| Contributor | ART |
| Admin Year Visited | Viewer Contributed |
| Friends of JCastle | |
| Jōkaku Hōrōki | |
| Shiseki no Yawa | |
| Yogo | |
