Matsudaira Kiyoyasu was the 7th lord over the Matsudaira clan during the Sengoku period (16th century) of Japan. Kiyoyasu was the grandfather of the exceedingly famous unifier of Japan, Tokugawa Ieyasu. Kiyoyasu soon gained control of the whole of northern Mikawa Province after the Saigo clan surrendered following four generations of conflict. Okazaki Castle was also built as a monument to the Matsudaira's power.