Iinawajō was built between the late 15th century and mid 16th century, but its current, complex layout dates to the late Sengoku Period. It was built by the Ogasawara Clan, nominal rulers of Shinano Province, to protect one Suwa side entrance into the valley where they had their main seats of power. Iinawajō was the largest of three forts built along the same mountain, along with Arashi Castle above it and Nishijo Castle at the very top.
Iinawajō is one of three castle sites located on the same mountain. It is the lowest of the three, the other two being Arashi Castle and Nishijo Castle. It is also the most extensive ruin in this network of fortifications, consisting of five integral baileys arranged in a "Λ" formation covering two diverging ridges of the lower mount. The top of the "Λ" is the shukuruwa (main bailey) where the two legs join up. From here I decided to take the ridge to my right, since I had to return in that general direction, passing through three more baileys and several terraced sub-baileys, as well as three horikiri (trenches dug into the ridge). I could see koshikuruwa (hip baileys) covering the mountainside to my left, on the inside of the "Λ". In the end I didn't have the chance to explore the other leg of the castle ruin, but it is made up of a stair-like row of many terraces from the top-down, followed by a large lower bailey protected above and below by a trench system - according to maps. The temple Jikōin now occupies the site of the Kyokan, which was an area at the foot of the mountain where the lord's residence was located.
|English Name||Iinawa Castle|
|Year Founded||Early 16th Century|
|Castle Condition||Ruins only|
|Historical Period||Pre Edo Period|
|Artifacts||Hori, Kuruwa, Dorui|
|Access||Midoriko Station on the Chuo Line; 10 minute walk to trail head|
|Visitor Information||24/7 free; mountain|
|Time Required||50 minutes|
|Location||Shiojiri, Nagano Prefecture|
|Coordinates||36° 5' 25.84" N, 137° 58' 22.94" E|
|Year Visited||Viewer Contributed|
|Added to Jcastle||2020|