Gassan Toda Castle is classified as a mountain castle, and is located in Shimane Prefecture. During the pre-modern age, it found itself within the borders of Izumo Province. It is associated with the Amako, Mōri clans. Dates in use: 1395 - 1611.

Considered one of the five great mountain castles of the Sengoku period. Certainly it's scale was great but what was the ingredient that allowed it to prosper in that hostile environment? This was a time before massive moats and unscaleable walls like those of Osaka castle. What protected this castle for 100's of years was the natural defenses its location offered which made it difficult for attacking armies.

Timeline

1195	The castle was built by the Sasaki clan.
1395	Amago Mochihisa was put in control of the castle.
1484	Amago Tsunehisa, a servant of the Kyogoku clan, was expelled.
1486	Tsunehisa recaptured the Castle.
1541	The first battle of Toda Castle - A combined force of Ouchi & Mōri troops were repelled.
1566	The second battle of Toda Castle - The Mōri were victorious.
1567	Amano Takashige became lord of the castle.
1569	Mori Akimoto enters the castle.
1585	Another Mōri enters the castle.
1591	The Yoshikawa clan were transferred here.
1600	The Horio clan were transferred here.
1611	The Hoiri clan transfer to the newly built Matsue Castle.

Historical recognition

Site	National Historic Site