Sekkiseki (殺気石, spirit reducing stone) is the stone that the walls of Seireitei are made of. It is a material known to negate all Reiryoku, similar to magnetic lodestones. The stone also forms a full spherical barrier around the city, stopping anything spiritual from breaching it.[1] It is also used in the walls of the cell Rukia Kuchiki was detained in as she awaited execution.[2]


  1. Bleach manga; Chapter 80, pages 9-10
  2. Bleach manga; Chapter 104, page 12