The Central Palaces were where the Shogun conducted daily life and government affairs. They were situated between the Front and Inner Palaces.
The Central Palaces' boundary with the Front Palaces was marked by the Tokeinoma chamber and a locked gate at the rear of the Kuroshoin, while they were connected to the Inner Palaces by two Osuzurōka corridors. The term nakaoku (Central Palaces) itself does not appear in Edo-period sources; it came into use only in the Meiji period.
Within the Central Palaces were rooms such as the Gozanoma, used by the Shogun for audiences with his council of elders (rōjū) and the Gokyūsokunoma, used for government business and other purposes. The interior layout of the palaces evolved according to the Shogun’s personal preferences and the positions of officials within them.

The Shogun’s daily schedule was largely fixed due to official ceremonies. He rose at sunrise, and after breakfast proceeded to the Inner Palaces to receive greetings from the ladies of the household, before spending the afternoon conducting government business in the Gokyūsokunoma. His day was thus very busy.
The Shogun also spent long hours in the Gokyūsokunoma and the Gozanoma, meaning his actual range of movement was surprisingly limited.
Among the positions within the Central Palaces were the osoba goyō toritsugi, who acted as intermediaries between the Shogun and the council of elders (rōjū); attendants (koshō) and minor chamber officials (konando), who took care of the Shogun’s personal affairs; and court physicians (okuishi).
These positions changed over time: for example, the sobayōnin chief aide to the Shogun was sometimes appointed and sometimes not. Quarters for officials of the Central Palaces were located according to the importance of their roles, with key positions such as the osoba goyō toritsugi situated closest to the Shogun’s rooms.