In the eastern section, soon after the castle's completion, Kuroda Zusho, Kuroda Yoshin, Mori/Bori Tajima, and Kuriyama Bingo (principal retainers) initially occupied the residences that were aligned along the edge of the northern moat of the inner castle, from the eastern edge of the inner castle to the Shimo-no-hashi Gateway. On the east of the Ni-no-maru, there was another residence which was initially occupied by Inoue Suo. These residences were continuously occupied by principal retainers from the time of the castle's completion through the last days of the Tokugawa Shogunate. The principal retainers who resided in these residences were often required by their lord's command to relocate there, as were the residents in the castle town. These retainers' residences, which were all approximately the same size, enabled an effective defensive disposition. A castle's garrison of soldiers is said to have been one to two soldiers per "tsubo" (4 sq.m.), and accordingly, each residence could contain 1000–2000 soldiers.