Akaiwa Castle
Akaiwajō is a yamajiro (mountaintop castle) ruin in the Tame area of Toyohashi Municipality. I think it is the closest yamajiro of note to Yoshida Castle on the plain below, and so perhaps may be visited by yamajiro fans visiting there. I went to Yoshidajō afterwards - my third or fourth visit. Akai
History
Akaiwajō was built around 1529 by the Makino Clan to repel the invasion of eastern Mikawa Province by Matsudaira Kiyoyasu who attacked Yoshidajō (then called Imahashijō). In that year Imahashijō fell to Matsudaira forces, and elements of the surviving Makino forces escaped to Akaiwajō. Nirengijō is situated between Akaiwajō and Yoshidajō, and it is also speculated that that castle's Toda Clan occupied Akaiwajō at some point.
Although the construction date of the castle is not known for sure, it is nonetheless thought to be a satellite fortification and mountain redoubt of Yoshidajō on the plain to the west. Akaiwajō also helped protect important trade routes.
Beneath Akaiwajō ('Red Rock Castle') stands the temple Sekiganji ('Red Rock Temple'). Sometimes temples beneath castle mounts indicate where a kyokan (residential annex) once stood, but in the case of Sekiganji it was apparently built originally on the mountain in the early Kamakura period, at which time it was called Hōgonji, and relocated downhill to make room for the castle. It appears that the names of the castle and temple both derive from the mountain, Akaisan.
Field Notes
Akaiwajō is a yamajiro (mountaintop castle) ruin in the Tame area of Toyohashi Municipality. I think it is the closest yamajiro of note to Yoshida Castle on the plain below, and so perhaps may be visited by yamajiro fans visiting there. I went to Yoshidajō afterwards - my third or fourth visit. Akaiwajō can be accessed by taking the Toyohashi streetcar to Akaiwaguchi Station (I had to transfer at Ihara Station; the streetcar line splits at the end in two different directions). From there it is a twenty minute walk to Sekiganji (赤岩寺), and the trail to the castle ruins is accessed from the temple. It doesn't take long to reach the castle ruins even though they are a little high up, because of the old and steep stone stairway going straight up the mountain. The trail to the castle goes by some large boulders and cliffs, one with a shrine atop. This terrain provided natural defence for the mountaintop fort.
Akaiwajō is a ridgetop fort with dorui (earthe ramparts), kuruwa (baileys) and a large horikiri (trench). The main bailey is small, but the dorui on the mountain-facing side is thick and tall. The trench below is wide, and has been cut through the mountain bedrock. This trench complex is a sight to behold.
There are some stepped baileys above the trench on the ridge, and then the natural ridge sweeps up without any fortification. Beneath the main bailey is a large terraced bailey. A segment of dorui climbs up from it to the main bailey. Some earthworks can be seen beneath the lower bailey, looking to me like a trench or a gate site. Maybe the castle's original entrance was here.
The maple leaves above the dorui were delightful. I even started climbing a tree for a better look at the effulgent foliage. These pictures also show Sekiganji and an altar building purched atop a rocky pinnacle en route to the castle site.
| Castle Profile | |
|---|---|
| English Name | Akaiwa Castle |
| Japanese Name | 赤岩城 |
| Founder | Makino Clan |
| Year Founded | 1529 |
| Castle Type | Mountaintop |
| Castle Condition | Ruins only |
| Historical Period | Pre Edo Period |
| Artifacts | Kuruwa, Dorui, Horikiri, &c. |
| Features | trenches |
| Visitor Information | |
| Access | Akaiwaguchi Station on the Toyohashi City Line streetcar; 25 min walk to trailhead. |
| Hours | 24/7 free; mountain |
| Time Required | 60 minutes |
| Location | Toyohashi, Aichi Prefecture |
| Coordinates | 34.76677, 137.44601 |
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| Admin | |
| Added to Jcastle | 2025 |
| Contributor | ART |
| Admin Year Visited | Viewer Contributed |
| Friends of JCastle | |
| Jōkaku Hōrōki | |
| Jōkaku Shashin Kiroku | |
| Umoreta Kojō | |
| Jōshi Yawa | |
| Shiro Rekishi Meguri | |
| Yogo | |
