Edo Castle
In 1582, during the turmoil following Oda Nobunaga's death, Hattori Hanzō advised Tokugawa Ieyasu to escape to Mikawa through the Kōga and Iga regions. Ieyasu, when he became the shōgun, employed ninja to guard Edo Castle—the headquarters of the Tokugawa shogunate—and to supply intelligence. He settled 200 men from the "Iga-ryū" in the Yotsuya neighborhood of Edo (Tokyo). Hanzo's Gate in Edo Castle took its name from the nearby residence of the Hattori clan.