Gassan Toda Castle

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Gassan Toda Castle 月山富田城

All that is left of Gassan Toda Castle are stone walls, and its location in the eastern part of Shimane Prefecture makes it quite difficult to visit, but Gassan Toda Castle is classified as one of the five great mountaintop castles (yamashiro) of the Sengoku Period, and it is rated quite highly by Japanese castle buffs.

Situated on top of Mount Gassan, a small mountain overlooking the Hirose River, it is not particularly high, but its steep sides makes it an easily defensible position.

Some type of fortification existed here since the Heian Period, but the first historical records refer to a castle controlled by the Sasaki clan in 1195.

Ruins of Gassan Toda Castle, Shimane Prefecture

History of Gassan Toda Castle

In 1395 the Amago, or Amako, a branch of the Sasaki controlled Gassan Toda Castle for most of the next 200 years. The Amago controlled quite a lot of territory, but during the Sengoku Period the Mori and the Ouchi both encroached on Amago land and they were pushed back until only their stronghold at Gassan remained.

In 1541 combined forces of the Ouchi and Mori laid siege to the castle, but its defenses were so good that after more than a year the Amago were victorious. 25 years later the Mori attacked again, but this time were victorious, due in part to treachery by one of the Amago vassals.

View from Gassan Toda Castle, near Matsue, Shimane Prefecture

Following their defeat at the Battle
of Sekigahara in 1600 the Mori were stripped of most of their territory and the Horio were moved in. Horio Yoshiharu decided the area around the castle was not ideal for building a castle town and economy so he started construction of Matsue Castle using in part material taken from the dismantled Gassan Toda Castle. Yoshiharu died before Matsue Castle was completed and is buried in a temple at the foot of Mount Gassan.

Gassan Toda Castle, Shimane Prefecture
Stone Walls of Gassan Toda Castle, Shimane Prefecture

At the base of the mountain there still remains some of the stone walls that made up the first level of defence. Here there were administrative buildings and temples, some of which still remain.

A wide path leads from here partway up the mountain to a level area underneath the final conical peak. Here there is a lot more stonework and a recently built replica of a guardhouse. From here a narrow path switchbacks up to the top of the mountain where the keep once stood.

On the top there are more walls and the base of keep, and, of course, great views up towards Lake Nakaumi. There is also a small shrine there. The original shrine was moved when the castle was built, but replaced after the castle was dismantled.

At the base of the mountain is a Michi no Eki (roadside service station) where a map of the trail to the castle other hiking trails around the mountain can be picked up. Next door is a Local History Museum with some displays relating to the castle.

Stone Walls of Gassan Toda Castle, Shimane Prefecture
Map of Gassan Toda Castle, Shimane Prefecture

Gassan Toda Castle

Tonda, Hirose-cho
Yasugi-shi
Shimane 692 0403
Admission: Free

Gassan Toda Castle Access

Gassan Toda Castle Ruins are located only 2 kilometers from the Adachi Museum and Gardens, so is only a short taxi ride from there. There is a bus from Yasugi JR Station to Hirose that stops a few minutes away from where the trail begins.

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