Ruinas del castillo de Iwamura, Ena

Iwamura Castle Ruins are located in Iwamura, Ena City, Gifu Prefecture, standing at 717 meters above sea level, making them the highest-elevated castle site in Japan and one of the country's three major mountain castles. The site is also listed among Japan's 100 Finest Castles. Because the hilltop is frequently enveloped in mountain fog, the castle earned the historical nickname "Kirigajo," meaning the Misty Castle, as the mist served as natural concealment from enemies.

The castle was originally constructed in 1221 by Toyama Kagetomo and endured for approximately 700 years before being demolished during the Meiji Restoration, a lifespan unmatched among Japanese castles. Its most significant historical figure is Lady Otsuya, the aunt of warlord Oda Nobunaga, who governed the castle following her husband's death and is recognized as one of Japan's rare female castle lords. After negotiating a truce through marriage to enemy commander Akiyama Nobutomo, she was ultimately captured and executed by Nobunaga's forces in 1575. Her legacy remains central to the town's identity.

The ruins today consist primarily of multi-layered stone walls and wells built into steep mountain terrain. Though the original structures no longer stand, the scale of the stonework conveys the military engineering of the original fortification. QR codes posted along the path allow visitors to view CG reconstructions of the castle on their smartphones. The path to the summit is approximately 2 kilometers in total and takes around 90 minutes to complete, passing through a cypress forest with uneven stone steps that can become slippery after rain. Entry to the ruins is free.

At the base of the hill, the preserved castle town stretches along a main street where over 40 percent of the traditional Edo-period wooden merchant houses remain standing. The Iwamura Shuzo Sake Brewery, founded in 1787, offers free visits including a tour of the brewing process and the opportunity to purchase the brewery's signature label. A local History Museum near the trailhead features a reconstructed Edo-period watchtower and views over the village.

Access from Nagoya takes approximately 80 minutes using public transport. Take the JR Chuo Line to Ena Station, then transfer to the Akechi Railway to Iwamura Station. The castle town and trailhead are a short walk from the station. Visitors arriving by car will find multiple parking lots near the town and closer to the trailhead; the road approaching the site is narrow and curvy. Entry to the castle ruins is free of charge.