Oka Castle (Mikawa)

From Jcastle.info

MikawaOkajouGlenn (5).jpg


Mikawa Oka Castle on the western outskirts of Okazaki City, Aichi Prefecture, was a riverside hirajiro (flatland castle) built by the Imagawa clan allied warrior Ikeno Daigaku during the Warring States period, but when exactly is unknown. Oka Castle is said to have been his main residence. Ikeno is believed to have been at the Battle of Okehazama in 1560, when Oda Nobunaga’s forces defeated the Imagawa clan, allowing Tokugawa Ieyasu, until then a hostage of the Imagawa, to be freed.

By 1561, Itakura Danjo Shigesada had become the lord of the castle. Itakura was previously master of Nakajima Castle near Okehazama, and had retreated to Oka. With the assistance of Suzuki Niemon, a traitor within Oka Castle, Tokugawa Ieyasu was able to attack the castle from the the river side, and the castle fell. Itakura Shigesada fled to Sawake Castle further along the Tokaido route, and was killed there during the second Battle of Azukizaka. In his place, Tokugawa allied Kawai Kankaiyuzaemon Munesada became the lord of the castle.

In 1585, Ieyasu ordered the renovation of Oka Castle turning it into a Tokugawa clan lodging house known as the Oka Goten, used on his trips to and from Kyoto. The remains seen today are thought to be the ruins of the lodging.

Visit Notes

Not much remains but part of an impressive large L-shaped dorui earthen mound and the dry moat on the southern side, which, looking at maps, appears to be part of the innermost gate complex. There is a small stone monument to the Oka Castle (erected in October 1940). The Oto River flows on the north side as a natural moat, and it appears as though some earthworks were undertaken to strengthen the riverbank, by digging out the lower section, forming a small kirigishi, cut embankment. The castle’s east side is protected by a cliff about 4m high, although difficult to see as it is now filled with towering bamboo. Other parts of the castle site are now fields, and private buildings.

There is next to no signage. The road leading to the actual site is too narrow for a vehicle, and there is no parking or U-turn space either. Along the road to the south of the site is a nagayamon (long gate) like farmhouse structure, there is room for cars to park opposite this, and it’s a short walk to the site. First you’ll see a small shrine and explanation board to your left and the previously mentioned forest of bamboo filling the 3-4m drop to your right. Proceeding behind the houses, one will see the dorui and former baileys amongst the tall bamboo.

Profile by Chris Glenn (edited by ART).

Loading map...

  • Entrance to the Oka Castle ruins
  • Oka Castle ruins remaioning dorui are quite impressive.
  • Remains of the dry moats below Mikawa Oka Castle's dorui.
  • Dry moat remains to the right, below the remaining dorui embankments at Mikawa Oka Castle.
  • Dorui around 3m high
  • The former inner compound of Mikawa Oka Castle.
  • Riverbank side of Oka Castle show what appears to be tiered embankments.
  • Old map of the Mikawa Oka Castle site. Detail of old map showing the location of the remaining part of the earthen walls.

Castle Profile
English Name Mikawa Oka Castle
Japanese Name 三河岡城
Alternate Names Oka-goten (岡御殿)
Founder Ikeno Daigaku
Year Founded Sengoku Period
Castle Type Flatland
Castle Condition Ruins only
Historical Period Pre Edo Period
Artifacts Karabori, Dorui
Features trenches
Visitor Information
Access Miai Station on the Meitetsu Nagoya Main Line; 17 minute walk
Visitor Information 24/7; Free
Time Required 20 minutes
Location Okazaki, Aichi Prefecture
Coordinates 34° 55' 57.43" N, 137° 12' 1.04" E
Loading map...
Added to Jcastle 2022
Contributor 豪谷
Admin Year Visited Viewer Contributed
Friends of JCastle
Oshiro Tabi Nikki
Jōkaku Hōrōki

(one vote)
Add your comment
Jcastle.info welcomes all comments. If you do not want to be anonymous, register or log in. It is free.



8 months ago
Score 0++
The ruins of Okajō in the Oka Township of Okazaki Municipality feature dorui (earthen ramparts) and karabori (dry moats), but the remains of the structure are only partial, and the layout and orientation of this square-shaped fort is mostly deduced from a prominent corner segment of its walls which still remain. The moat segment continues on but much shallower a little way into the bamboo grove. It is thought that the northern perimeter of the castle was protected by the river terrace. The fort was otherwise a hirajiro(flatland)-type fortification.