Ibo Castle (Mikawa)
Ibojō is a hillside fortified residence ruin in Homi Township, Toyota Municipality. It is the proto-modern successor to Sengoku period forts that occupied the surrounding hilltops, and another residence site now referred to as Ibokojō ('Old Ibo Castle'). As such, it was also called Oyamamaejō ('Cast
History
Ibojō was built by Niwa Ujitsugu in 1600. Ujitsugu, the eldest son of Niwa Ujikatsu, had originally served Oda Nobukatsu, but became the vassal of Tokugawa Ieyasu. Following the battle of Sekiǵahara he was awarded with 10,000 koku worth of territory in Ibo, establishing Ibojō. 10,000 koku (said to be equivalent to 50,000 bushels of rice, for some context; or enough rice to feed ten thousand people for a year) is the minimum required value of a daimyō's territory. Thus, Niwa Ujitsugu was a daimyō, and Ibojō was his castle, though it was not a very large fortress and was more akin to a residence with minor fortifications.
In 1601, Lord Ujitsugu died and his successor, Niwa Ujinobu, took over (he was the equivalent to a sixth grader at that time; he would not have already had a proper name by the time his father came to serve the Tokugawa, yet the 'nobu' in his name is that of the old liege Oda Nobuo perhaps? Interesting). In 1638, Lord Ujinobu was transferred to Iwamurajō with territory valued at 30,000 koku. Ibojō was then abandoned. The Ibo Domain was re-established for Honda Tadaharu in 1681, and governed from Ibo-jin'ya, situated to the north of where Ibojō had been. Ibo-jin'ya was in turn decommissioned in 1710.
Field Notes
Ibojō is a hillside fortified residence ruin in Homi Township, Toyota Municipality. It is the proto-modern successor to Sengoku period forts that occupied the surrounding hilltops, and another residence site now referred to as Ibokojō ('Old Ibo Castle'). As such, it was also called Oyamamaejō ('Castle before the Mountains') in order to distinguish it from those earlier sites. Of ruins little remain except for some residual earthworks and masonry. Unfortunately, these ruins are on private property on either side of a small lane. The remnant dorui (earthen rampart) can be seen from the lane because of the tendency of Japanese people not to build fences around their property (the many fortified manor halls of medieval times can attest that this is a modern development but a welcome one). From the road on the hillside above I also spied some suggestive terracing and embankments. As for the stonework which is supposed to remain, that seems to be hidden from public view, but it was part of a retaining wall built in two narrow bands along an embankment to the south of the site.
| Castle Profile | |
|---|---|
| English Name | Ibo Castle (Mikawa) |
| Japanese Name | 三河伊保城 |
| Alternate Names | Oyamamaejō (御山前城 ) |
| Founder | Niwa Ujitsugu |
| Year Founded | 1600 |
| Castle Type | Hilltop |
| Castle Condition | Ruins only |
| Historical Period | Edo Period |
| Artifacts | Dorui |
| Features | stone walls |
| Visitor Information | |
| Access | Homi Station on the Aichi Loop Line; 15 min walk |
| Hours | 24/7 free; mountain |
| Time Required | 10 mins |
| Location | Toyota, Aichi Prefecture |
| Coordinates | 35.13887, 137.12854 |
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| Admin | |
| Added to Jcastle | 2025 |
| Contributor | ART |
| Admin Year Visited | Viewer Contributed |
| Friends of JCastle | |
| Jōkaku Hōrōki | |
| Oshiro Tabi Nikki | |
| Jōshi Meguri Bibōroku | |
| Yogo | |
