text: The forces of Honda clan under Tadakatsu's vassal, Kaji Masamichi, entered the castle and then go up to the top floor, where Masamichi raised a black flag to the outside to signalling their allies to follow suit entering the castle.Iwatsuki castle has fallen in May 22. In May 14, Tokugawa troops detachment under Tadakatsu, Shimada Toshimasa, and Torii Mototada were attaching themselves to the Toyotomi army besieging Hachigata Castle, with total strength of 35,000. On June 13, When Tadakatsu was deployed under Asano Nagamasa, he carried a cannon up a nearby mountain and began firing it into the castle, which causing severe damage to the castle, prompting its defender, Ujikuni, surrendered the castle in exchange for sparing the lives of the castle's soldiers. the castle fallen in June 14. During this campaign, Tadakatsu also subdued Mangi Castle, which he temporarily settled in. Later in the same year, when Ieyasu was transferred to the Kantō region,, Ieyasu promoted him from daimyō/lord of the Ōtaki Domain ( koku) in Isumi District, Kazusa Province, to the Kuwana Domain ( koku) as a reward for his service. In addition, his son Honda Tadatomo became daimyo of Ōtaki. 