Qualla: Iwadono Castle: The Mountain Fortress That Outlasted Its Lord

Iwadono Castle: The Mountain Fortress That Outlasted Its Lord: Introduction

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Midori, CC BY 3.0. Oyamada Nobushige thought switching sides would save his life. In 1582, as the armies of Oda Nobunaga and Tokugawa Ieyasu swept through Kai Province destroying the Takeda clan, Nobushige abandoned his master and surrendered Iwadono Castle to the invaders, hoping for mercy. Oda Nobunaga executed him instead, despising the betrayal. The castle on Mount Iwadono lost its military purpose that day, and the mountaintop fortifications were never garrisoned again. Four centuries later, the ruins draw hikers instead of warriors -- people climbing the same steep trails that once made this yamajiro nearly impregnable, arriving at a summit where stone walls crumble into wildflowers and the view of Mount Fuji stretches unbroken across the valley.

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Image: Midori | CC BY 3.0

Iwadono Castle: The Mountain Fortress That Outlasted Its Lord: Watching the Road Below

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Bryanmackinnon, CC BY 4.0. Iwadono Castle was built in the early 16th century by the Oyamada clan, local retainers of the powerful Takeda family who controlled Kai Province -- present-day Yamanashi Prefecture. The site was chosen for a specific reason: Mount Iwadono commands a view of the Koshu Kaido, the ...

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Image: Bryanmackinnon | CC BY 4.0

Iwadono Castle: The Mountain Fortress That Outlasted Its Lord: The Tiger's Paw

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Koda6029, CC BY-SA 4.0. Under Takeda Shingen, the legendary warlord who dominated central Japan from the 1540s through his death in 1573, Iwadono Castle was significantly expanded. Shingen understood that controlling the eastern frontier meant holding the mountain passes, and Iwadono sat squarely on tha...

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Image: Koda6029 | CC BY-SA 4.0

Iwadono Castle: The Mountain Fortress That Outlasted Its Lord: A Lord's Miscalculation

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Koda6029, CC BY-SA 4.0. Takeda Shingen's death in 1573 began the slow unraveling of the Takeda domain. His son Katsuyori suffered a devastating defeat at the Battle of Nagashino in 1575, and by 1582 the combined forces of Oda Nobunaga and Tokugawa Ieyasu were closing in for the final destruction of the ...

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Image: Koda6029 | CC BY-SA 4.0

Iwadono Castle: The Mountain Fortress That Outlasted Its Lord: Stone and Root

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Jun OHWADA, CC BY 2.0. What remains on Mount Iwadono today reads like a geological autobiography of a castle. The terraced baileys are still visible as flat platforms cut into the mountainside, their edges softened by centuries of erosion. Stone wall foundations poke through the undergrowth in places, ...

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Image: Jun OHWADA | CC BY 2.0

Iwadono Castle: The Mountain Fortress That Outlasted Its Lord: The Summit Reward

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Bryanmackinnon, CC BY 4.0. The hike from Otsuki Station to the castle summit takes roughly one to one and a half hours, climbing steadily through forest on well-maintained trails. The effort pays off with one of the finest panoramic views in the region. Mount Fuji dominates the southern horizon, rising in ...

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Image: Bryanmackinnon | CC BY 4.0