* Image is for illustrative purposes only.Iwadono Castle
岩殿城
Iwadono Castle is a historic castle in Chūbu dating from the Sengoku Period (15th–16th century), whose lord was Oyamada clan (Takeda retainers) → Oyamada Nobushige.
Overview
Iwadono Castle occupies the sheer cliffs of Mt. Iwadono (634 m) in Otsuki City, Yamanashi Prefecture — a natural fortress so formidable that the site was known as virtually impregnable. Developed and maintained as the seat of the Oyamada clan, powerful retainers of the Takeda, the castle reached its peak of prosperity under Oyamada Nobushige, the final lord. When the Takeda clan fell in Tensho 10 (1582), the lord Takeda Katsuyori attempted to flee to Iwadono Castle, but Nobushige treacherously refused him entry, forcing Katsuyori to take his own life at Mt. Tenmoku (Keikokuin). Nobushige himself was subsequently executed by Oda Nobutada, and Iwadono Castle fell into ruin. The vertically soaring rock faces and surviving stone-pile remains convey the castle's legendary impregnability and form an iconic landscape of Otsuki City.
Connection to Swords
Iwadono Castle's sword connections are inseparable from its role as a Takeda stronghold. Takeda Shingen was among the most celebrated sword collectors of the Sengoku period, and several blades associated with him are designated National Treasures or Important Cultural Properties today. Kai Province (present-day Yamanashi) sustained a tradition of provincial sword-smithing known as the Kōshū school, whose smiths supplied the Takeda military machine. Iwadono Castle stood at the front line of this Takeda sword culture, and its fall in 1582 marked the collapse of the last major Sengoku-era domain still resisting Nobunaga's unification — a pivotal moment in Japanese sword history as the battlefield era gave way to the Edo period's aesthetic sword culture.
Highlights
- Sheer cliffs of Mt. Iwadono — vertical basalt faces forming the castle's natural defense, with panoramic views of Mt. Fuji and the surrounding mountains
- Stone-pile remains — surviving Sengoku-era stone construction near Maruyama Park below the summit
- Site of Takeda Katsuyori's betrayal — the tragic focal point of the Takeda clan's final hours in 1582
- Iwadono hiking trail — accessible on foot from Otsuki Station, popular as a Mt. Fuji viewpoint as well as a castle ruin
- Keitoku-in Temple (Kōshū City) — the site of Takeda Katsuyori's death, with traditions of sword offerings associated with the Takeda clan
* Opening hours and admission fees are subject to change. Please check the official website before visiting.