Ishikawa Kazumasa, a notable retainer under Tokugawa Ieyasu, who served him since childhood, when they were both hostages under the Imagawa. After 1560, when Ieyasu abandoned the Imagawa, Kazumasa then became a valued retainer and administrator under him. During the year 1562, when Ieyasu managed to convince Imagawa Ujizane to release his family, Kazumasa acted as guardian of the Imagawa, which at the time was a very dangerous task. Kazumasa then later decided to retire and live with his son Ishikawa Yasumichi, until he died in 1609.