The Underground Assembly Hall is where the Central 46 meets. It is an octagonal structure located in a large open space within the main building, and was also referred to as the Diet Building.
The Seijōtōkyorin (清浄塔居林, Tranquil Forest of Residential Towers; Pure Pagoda Forest) is where the Central 46's members reside. It is the only place in all of Seireitei that is completely off limits to all except the Central 46, no matter what reason they may have.