* Image is for illustrative purposes only.Iwamura Castle
岩村城
Iwamura Castle is a historic castle in Chūbu dating from the Founded 1203 (Ken'nin 3), whose lord was Katō Kagenori / Tōyama Kageto / Lady Otsuya.
Overview
About the Castle
Iwamura Castle is a mountain castle situated in Ena City, Gifu Prefecture, at an elevation of 717 meters, and is counted among Japan's Three Great Mountain Castles alongside Bitchu Matsuyama Castle and Takatori Castle. It is known as the highest mountain castle constructed within Japan, earning the mystical epithet "Castle in the Mist." According to tradition, it was founded in 1203 (Kenin 3) by Katō Kagenari, a retainer close to Minamoto no Yoritomo, and subsequently became the primary stronghold of the Tōyama clan (Tōnō Tōyama) and the central castle of the Tōnō region.
The Legend of the Female Castle Lord
The principal reason Iwamura Castle became known throughout the nation was the presence of a "female castle lord." Following the death of Tōyama Kagetō, his wife Lady Otsuya (aunt of Oda Nobunaga) assumed the position of female castle lord, managing the castle and governing Tōnō. Though Otsuya enjoyed Nobunaga's profound trust as his aunt, she was drawn to the skillful diplomacy and personal magnetism of Akiyama Tobutomo (also known as Nobutomo), a senior retainer of Takeda Shingen. She eventually married Akiyama and transferred her allegiance to the Takeda faction. Incensed by this "betrayal," Nobunaga defeated Takeda Katsuyori at the Battle of Nagashino in Tenshō 3 (1575). Later that same year, his eldest son Oda Nobutada recaptured Iwamura Castle and executed both Lady Otsuya and Akiyama Tobutomo by inverted crucifixion.
A Tragic Legacy
This tragic outcome became a byword for the mercilessness of the Sengoku era, immortalizing Iwamura Castle as the "Castle of the Female Lord" in history. The incident—in which even Nobunaga coldly ordered the execution of his own aunt—exemplifies the ruthlessness and intrigue that defined the age of provincial warfare. Thereafter, during the Edo period, various daimyō including the Matsudaira and Niwā clans served as castle lords, and the domain persisted as Iwamura han until the end of the bakufu. The stone walls are particularly notable for their distinctive construction method called the "six-tiered wall," and the grand array of stonework creates a phantasmal landscape floating in the mist.
Architecture and Structure
Iwamura Castle's stone walls possess a distinctive structure in which natural cliff faces and constructed stonework are unified, with evidence of ingenuity visible throughout the construction on steep mountain terrain. The stone wall on the south side of the main citadel, known as the "six-tiered wall," is especially magnificent. Though completed in the late Edo period, it embodies the refined excellence of castle architecture in both scale and precision. The castle town features sake breweries of Iwamura Brewery and long-established merchant houses, and has been designated an Important Preservation District for Groups of Historic Buildings, maintaining the historic streetscape of former times.
The Castle Town's Development
One corner of the castle town preserves living traditions of Tōnō cuisine such as "kankaramochi" and "gobei mochi," and a historical pilgrimage combining a climb to the castle with a stroll through the castle town offers visitors to Iwamura a singular experience. Following the broadcast of the NHK Taiga drama "Onna Jōshu Naotora" (2017), Iwamura Castle re-gained attention as a site connected to a female castle lord, drawing numerous castle enthusiasts from across the nation.
Natural Setting and Landscape
The mist in Iwamura runs particularly deep from autumn into early winter, and the sight of the stone walls at the summit floating upon a sea of mist is celebrated as a spectacular vista rivaling the "sky castle" of Takeda Castle (Hyōgo). Standing at the 717-meter summit and gazing upon the mountain ranges of Tōnō stretching below, contemplating the turbulent life of Lady Otsuya, visitors experience history not as mere knowledge but as a living reality pressing upon the heart.
Connection to Swords
Iwamura Castle, situated in the Tōnō region of eastern Mino, stands at the eastern edge of the Mino-den swordsmiths' cultural sphere, which centers on the city of Seki. As one of the Five Great Traditions, Mino-den shines brilliantly in Japanese sword history. Master bladesmiths such as Kanemoto and Kanesada forged practical swords renowned for their qualities—"won't break, won't bend, cuts well"—that earned overwhelming support from Sengoku warlords. The Tōyama clan, successive lords of Iwamura Castle, built their stronghold in the very heart of this celebrated Mino blade-producing region, and their relationships with the area's bladesmiths are believed to have been deep. Of particular significance is the role of blades in the dramatic narrative surrounding Lady Otsuya and Akiyama Nobutomo, the brilliant strategist of Takeda Shingen. Akiyama Nobutomo, counted among Takeda's Twenty-Four Generals, was a formidable commander who led the Takeda clan's elite cavalry corps in their campaign to conquer Tōnō. However, Kai Province was not a major sword-producing center, and the renowned swords in the Takeda clan's collection—such as Sōsansamoniji—were in fact forged by bladesmiths from other provinces: Sōshū, Bizen, and Echizen. No independent sword-making school called the "Kōshū tradition" ever became established in Kai. At the Battle of Nagashino (1575), the Takeda cavalry corps suffered devastating losses from Oda and Tokugawa musketeers, marking a historic turning point from close-quarters combat with swords and spears to long-range warfare with firearms. After Oda Nobunaga retook Iwamura Castle, the region came under Oda domain control, and the blade and armor culture of Mino and Owari extended into Tōnō. Throughout the Iwamura han period, the castle-town bladesmiths were protected as essential craftspeople supporting the armament of domain samurai. Today, the Iwamura Historical Museum in Ena City displays arms and blades associated with Iwamura Castle, where visitors can study the castle's history from the age of Lady Otsuya through the Edo period while learning about the evolution of the region's blade culture. Tōnō's blade culture embodies both the practical efficacy of Mino-den and the steady, unpretentious spirit of the mountain warriors, possessing—like the castle's steep stone ramparts—plain genuine strength.
Highlights
- Six-tiered stone walls — the dramatic southern honmaru walls
- Sea of clouds in autumn/winter — castle ruins floating in morning mist
- Female castle lord Lady Otsuya historical sites
- Iwamura castle town (Important Preservation District) — sake breweries and old merchant houses
- Ena City Iwamura Historical Museum — arms and swords from the castle's history
* Opening hours and admission fees are subject to change. Please check the official website before visiting.