The Tanaka Castle Ruins, designated as a historical site by Fujieda City, feature the only circular castle defenses in Japan, built in a concentric fashion around the keep. It was a formidable stronghold in its day, surrounded by wetlands that made it difficult to attack and easy to defend.
Once an important military base for the Takeda clan, the castle came under attack by Tokugawa Ieyasu more than five times in the span of seven and a half years starting in 1574, and many fierce battles took place here.
In 1582, Tokugawa Ieyasu finally took Tanaka Castle as his own. While still in his prime in his thirties, Ieyasu fought heroic battles against Takeda army for control of Suruga Province and Totoumi Province, cultivating the qualities that would lead him to eventually become ruler of all Japan.

Ieyasu, acting as the retired shogun (ogosho) relocated from Edo to Sumpu Castle. He enjoyed falconry, and often practiced the sport in the vicinity of Tanaka Castle, visiting the castle at least fifteen times in the seven years leading up to his death.

In January 1616, when Ieyasu was visiting Tanaka Castlle to practice falconry, he suffered severe stomach pains.
According to one story, this happened because Ieyasu ate too much sea bream tempura. A few days later he returned to Sumpu Castle to recuperate, but on April 17 at the age of 75, he reached the end of his tumultuous life.

From his prime to his passing, Ieyasu had deep ties to Tanaka Castle. The roads around the castle curve to form concentric circles, unlike any other castle in Japan. Take a stroll around the castle while turning your thoughts to the times of the shogun.