Honmaru was the resident of the Shogun and his wives, Ninomaru was the resident of the shogun's real mother and concubines of former Shogun, and Nishinomaru was the residence of the successor couple and the retired shogun couple.
本丸は将軍夫妻、二丸は将軍生母やかつての将軍仕えていた側室、西丸は世嗣夫妻や大御所夫妻が住まいとしていた。