Seireitei is in the center of Soul Society. Seireitei is a circular shiro with four main entrances, ten days walk apart, each guarded by one of the Gatekeepers. These gates are collectively called the Four Great Pure Soul Gates: these gates are made up of the Northern Black Ridge Gate , the Eastern Blue Stream Gate, the Southern Red Hollow Gate, and the Western White Way Gate. The walls of Seireitei are made of Sekkiseki, 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 Soul King Palace, located in an inner dimension.