Ohkusa Castle (Aichi)
Ôkusajō is a hilltop fort ruin in the Ôkusa area of Nagakute Municipality (spread between the borders of the localities of Irinohara, Mizunoiri, Gomae and Kitaura). Ruins are mostly earthworks, including terracing of the hillside and trench excavations. The layout is complex, with a hodepodge of bai
History
Ôkusajō has its origins in the Kamakura period. It was destroyed during the Jōkyū War (1221) and left abandoned for several centuries until being rebuilt in 1579 by Mori Nagayoshi. Fukuoka Shinsuke was the castellan in the Sengoku period. Following the battle of Nagakute in 1584 and Mori Nagayoshi's death, fleeing soldiers sought shelter at Ôkusajō, and Tokugawa forces attacked, though they would ultimately retreat to avoid clashing with reinforcements sent by Hashiba Hideyoshi. The castle was damaged during the Komaki-Nagakute War and abandoned thereafter.
Field Notes
Ôkusajō is a hilltop fort ruin in the Ôkusa area of Nagakute Municipality (spread between the borders of the localities of Irinohara, Mizunoiri, Gomae and Kitaura). Ruins are mostly earthworks, including terracing of the hillside and trench excavations. The layout is complex, with a hodepodge of baileys clustered around the hillside. The top of the hill has been artificially levelled, but it seems somewhat to me like it may have been further modified in modern times.
I entered the site via the causeway of the Kumano shrine, and along here there is a tall tatebori (climbing trench) with a dorui (earthen rampart) segment climbing parallel. This feature is quite clear on the ground, as it were, but overgrown in parts and difficult to photograph.
The east bailey is the topmost bailey, but the main bailey is in the western portion of the castle site, now separated by a road. There is a large dorui embankment on the western side of the main bailey. This is overgrown. Between the main bailey and the southwest bailey is a karabori (dry moat) and some dorui. To the east of the site a horikiri (trench) cuts the hilltop off from a connecting ridgeline.
Medieval fortification features are in evidence at this site, but most of the remains do not clearly come into focus, and it is hard to appreciate the overall structure. Some parts are off-limits, under plough, or very overgrown, so a full exploration is taxing. The hillside has many small terraced baileys, so that I'm sure I did not see them all. Overall I'd say this is a pro-level site for castle-explorers.
This site is Ôkusajō in Nagakute Municipality, Aichi Prefecture, formerly Aichi County of Owari Province. The county gives its name to the prefecture. There are several other sites called 'Ôkusajō' in Aichi Prefecture / Owari Province. This site is not to be confused with Chita-Ôkusajō (the one with the mogi tenshu (folly keep)), also in Owari Province, or Mikkawa-Ôkusajō, also in Aichi Prefecture. So far, out of the thousands of sites I've visited, I've been to three castle sites called 'Ôkusa' and all of them are in Aichi Prefecture!
| Castle Profile | |
|---|---|
| English Name | Ohkusa Castle (Aichi) |
| Japanese Name | 愛知大草城 |
| Founder | Mori Nagayoshi |
| Year Founded | 1579 |
| Castle Type | Hilltop |
| Castle Condition | Ruins only |
| Historical Period | Pre Edo Period |
| Artifacts | Karabori, Kuruwa, Horikiri, Dorui, &c. |
| Features | trenches |
| Visitor Information | |
| Access | Nishi-Kōen Station on the Tōbukyūryō Line 'Linimo' |
| Hours | Access Limited |
| Time Required | 60 mins |
| URL | Castle Website |
| Location | Nagakute, Aichi Prefecture |
| Coordinates | 35.18766, 137.06613 |
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| Admin | |
| Added to Jcastle | 2025 |
| Contributor | ART |
| Admin Year Visited | Viewer Contributed |
| Friends of JCastle | |
| Jōkaku Hōrōki | |
| Oshiro Tabi Nikki | |
| Jōkaku Shashin Kiroku | |
