Location: The Niwa District in Owari Province. Located in the eastern portion of the Nōbi plain, south of Inuyama castle and north of Komaki castle; near the Kiso road linking central Owari and the town of Kiso in Shinano Province.
Features: Built on a plain.
History: Built in the Eishō period (1504 to 1521) by Oda Hisanaga, a shugo in Owari. In 1558, Oda Nobukiyo, lord of Inuyama and a retainer of Nobunaga, attacked and captured Gakuden castle and made it a support base. A rebellion by Nobukiyo against Nobunaga in 1562 led to Nobuliyo fleeing Inuyama castle, and Gakuden was occupied by Sakai Masahisa, Nobunaga’s retainer. His eldest son, Sakai Hisatsune, died in 1570 at the battle of Anegawa. Masahisa died later that year in battle at Katada in Ōmi Province, and Kajikawa Takamori became lord of Gakuden. In 1584, Gakuden served as a forward base in the battle of Komaki and Nagakute, during which Toyotomi Hideyoshi’s retainer, Hori Hidemasa, served as its lord, and Hideyoshi himself lodged at the castle. After this battle, the castle was abandoned.