Seireitei

is in the center of Soul Society.

Overview
Seireitei is a circular shiro with four main entrances, ten days walk apart,, each guarded by a Gatekeeper. These gates are collectively called the
 * these gates are made up of the (in the North), the  (in the East), the  (in the South) and the  (in the West)  . The gates are so heavy that it takes the full might of Jidanbō Ikkanzaka to lift one, while during the Bount-led attack on Seireitei, siege machines were needed to open the gates. There are, however, doors within the gates, as seen when Momo Hinamori first entered the Shin'ō Academy.

The walls of Seireitei are made of, a rare type of stone known to negate all Reiryoku, similar to magnetic lodestones. The stone also forms a spherical barrier around the city, extending above and below, stopping anything spiritual from breaching it from ground level, from the sky or from underground.

The wall that surrounds the Seireitei is commonly held up, only closing down when there is an emergency. When it is not down protecting the Seireitei, the wall protects the Palace of the Soul King, located in an inner dimension.

Information about the Seireitei is confidential. What is known is that in the center of the Seireitei is a white tower known as the Senzaikyū, where criminals are imprisoned (similar to death row); on the hill adjacent to it is the Sōkyoku, where prisoners are executed. Those permitted to live in the tranquility of the Seireitei are Shinigami and the few families of the nobility. Shinigami live in the Division barracks, while high-ranking officers commute from their own homes.

The majority of the residents of Seireitei, nobility and Shinigami alike, do not interact with the citizens of Rukongai. However, residents of Rukongai, like Renji and Rukia, are allowed to apply for the Shin'ō Academy, which is often the only escape from the poorest conditions of Rukongai.

Following the Quincy War 1000 years ago, the Quincy who would later become the Wandenreich fled to the Seireitei and used Reishi to create space in the "shadows", effectively creating a world within the Seireitei, unseen to outsiders. These Quincy were able to move between their world and the Seireitei, as they were technically there to start with. The Wandenreich can absorb the Reishi particles of the Seireitei to reveal their hidden world.

Gatekeepers
The are protected by the. They are all giants who have the strength to lift the gates made of Sekkiseki.